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5th International Conference on Rain Water Cistern Systems
"Rainwater Catchment for Future Generations"
Keelung, Taiwan, R.O.C. - August 1991

Section 1: Keynote Papers

Paper 1.1

Progress Of International Conference On Rain Water Cistern Systems

Yu-Si Fok, Professor
University of Hawaii at Manoa, U.S.A.

Abstract

As the subject-conference-series has been progressed to the 5th conference, it is very appropriate to document the back-ground, the birth and highlights of each conference for the benefit of the future development of this conference series. This paper is based on an invited keynote paper presented at the 2nd conference which has not been, published. The development and highlights of subsequent conferences have. been included in this paper. In addition, the initiation and establishment of the International Rainwater Catchment Systems Association (IRCSA) are also included. This paper is intended to put important events of each conference in the record. The request of past conference participants to contribute their own experience in this conference series has also been made.

Paper 1.2

Progresses Of The U.N. Water Decade And Rainwater Catchment Systems

Yu-Si Fok
University of Hawaii at Manoa, U.S.A.

Show-Chyuan Chu
Taiwan Ocean University, Keelung, Taiwan

Abstract

According to a report by UNDP in December, 1989 (The progresses of the United Nations' International Drinking Water Supply and Sanitation Decade 1981-1990,) on the water decade, there are about 55% targeted population in-developing countries has received :safe drinking water supply while only 17% of. Those received sanitation disposal of their waste. This paper has made an assessment of factors that affects this imbalanced of development drinking water supply and sanitation during the U.N. water decade. In addition, possible approaches that may be used to fulfill the U.N. Water Decade's objectives are also presented. In the process of the assessment, progresses of rainwater catchment systems have examined. The Thailand Jar Rain Water Catchment Program is cited as an outstanding drinking water supply program which should be recommended to the U.N. Water Decade decision makers and planners for promotion.

Paper 1.3

The Contribution of Rainwater Catchment Systems to the International Drinking Water Supply and Sanitation Decade : Lessons from Thailand

John E. Gould
University of Kent, U.K.

Abstract

Compared to the lofty goals set for the IDWSS Decade in the late 1970's, the achievements in many developing countries seem disappointing. The Decade did, nevertheless, coincide with a period of renewed interest in Rainwater Catchment Systems (RWCS) technology and the implementation of many millions of tanks world-wide made a significant contribution to improving both access and quality of domestic water supplies for tens of millions of people. Although, during the last decade, thousands of individual community projects around the globe have recognized the potential for RWCS operating in tandem with other water supply technologies for meeting their water supply needs; only one national government, that of Thailand, has wholeheartedly taken the technology on board. Since the mid-1980's, Thailand has actively promoted and supported RWCS through the Thai Jar Programme and has incorporated it into its water supply provision plans at local, regional and national .levels. The result. of this was the construction of around 10 million 1-2m3 jars and hundreds of thousands of 6-12m3 rainwater tanks by the end of the Decade and Thailand becoming one of the few countries to even approach the IDWSS Decade targets for rural water supply provision.

Despite its unprecedented scale and success, the rapid implementation of the Thai jar programme encountered a variety of problems. These provide useful lessons for others and are examined. in this paper. They include:

  1. The importance of conducting health and hygiene education campaigns associated with the operation and maintenance of the RWCS before and during their implementation, not afterwards. 
  2. The need for awareness about the adverse affects caused by the rapid commercialization of tank/jar construction and implementation on their effective operation and maintenance. 
  3. The importance of research and of communicating the findings of such research widely and rapidly, particularly aspects relating to potential design problems or health hazards related to rainwater supplies.

Section 2: Catchment Water Quality Regulation

Paper 2.1

The Bacterial Content Of Cistern Waters In Hawaii

Roger S. Fujioka, Steven G. Inserra, Robert D. Chinn
University y of Hawaii, USA

Abstract

The drinking water quality of 15 cistern systems in Honolulu, and 3 cistern systems on another island (H waif) in the State ofHawaii was evaluated. These cistern waters an be expected to meet turbidity, chloride, nitrate and pH levels established by USEPA for drinking water. However, the bacterial (total heterotrophic fecal coliform, E. coli, fecal streptococci) c oncentrations in these cistern waters usually exceeded drinking water standards. Low levels of. C. perfringens and salmonella bacteria were also recovered from :some cistern reservoir tanks. Higher concentrations of bacteria were' recovered from cistern reservoir tanks than from household faucet sources. The cisterns in Hawaii are susceptible to contamination by indicator bacteria via multiple sources an cannot be expected to meet bacterial drinking water standards. e recommend that the portion of water to be used for drinking be disinfected and standards specifically for cistern waters based on fecal coliform or E'.coli be established.

Paper 2.2

Improving Cistern Water Quality

J. Hari Krishna
University of the Virgin Islands, U.S.A.

Abstract

As cistern water systems become increasingly popular around the world, it is important that adequate attention be given to maintaining and improving cistern water quality. Periodic water testing, to at least determine the presence of coliforms, should be initiated in those areas where cistern water is used for drinking purposes. A number of relatively simple techniques are discussed in this paper, which will assist in improving cistern water quality. These include roof maintenance and removal of overhanging vegetation, installation of screens and first-flush devices, ultraviolet radiation, exposure to sunlight and the use of silver compounds in small quantities. The specific choice of a disinfection method depends upon the personnel and other resources available-in any given area or region.

Paper 2.3

Rainwater Quality: Pathogens And Heavy Metals

Wanpen Wirojanagud
Khon Kaen University, Thailand

Abstract

The quality of rainwater samples collected from collecting system (roof and gutter), storage containers (both outdoor and indoor) were evaluated both bacteriologically, using indicator organisms and pathogen isolation, and chemically by analysing heavy metal concentrations. The source of bacteriological contamination was investigated employing the ratio of fecal coliform to fecal streptococci (FC:FS). Information on saitary practices was also investigated.

Approximately 60-91 %, 34-78 %, 43-78 %, and 10-33 % of samples collected from collecting system and storage containers did not meet the drinking water quality standard expressed in terms of total bacterial count, total coliform, fecal colliform, and E.Coli, respectively. About 79-84 % of samples collected from roof and gutter had FC:FS ratios of less than 1, indicating the source of contamination was animal. While about 39 % and 47 % of samples collected from in-house containers had FC:FS ratios of less than 1 and greater than 4 respectively, which indicated the contaminating sources were both animal and human.°The contamination induced by human was mainly caused by unsanitary practices on water handling and usage of the villagers.

Pathogenic contamination was found approximately 1.1 % of samples collected,from such sampling points. The pathogens identified were Salmonella gr.E. and gr.C, V. parahaemolyticus, and Aromonas. The heavy metals analysed in this study included Cd, Cr, Pb Cu, Fe, Mn and Zn. Most of the heavy metal concentrations taken from various sampling points compared favorably with WHO drinking water standards with two exceptions, Mn and Zn. However, Mn and Zn are considered to affect the asdthetic quality of drinking water only and were therefore not significant to health.

The findings from this study indicate that any health risk evolving from the consumption of stored rainwater would be due to bacteriological contamination rather than heavy metal contamination.

Paper 2.4

Qualite Des Eaux Des Citernes De Captage Wea De Pluie Au Sahel

O. Guene, C. Tandia, Or. C. S. To
CREPA, Burkina Faso

Abstract

Despite its existence for several centuries, the development of rainwater roof catchment system faces great difficulties in African countries. particularly in the Sahel. Obstacles for its expansion include the scepticism and uncertainty of local populations concerning the safety of rainwater when store for long time.

In order to promote this technology in African co ntries, CREPA and CIEH have established a program for construction of rainwater c tern systems throughout Ouagadougou in Burkina Faso. Also, CREPA has extended his program to include all other countries which are members of the Centre through demonstration projects. At the samr time, CREPA examines regularly the water quality during conservation. According to WHO standards, rainwater stored is drinkable Sometime , pollution due to animals is noticed. But, the lack of organic matters in stored rainwater precludes the growth of micro-organisms

In conclusion, when well constructed, the rainwater cistern system can be an alternate source of water supply.

Paper 2.5

Microbial Levels in Cistern Systems: Acceptable or Unacceptable

Dennis J. Lye
Environmental Protection Agency, USA

Abstract

The acceptance of cistern systems as a source of potable water and as a possible source for non-domestic use is dependent upon the quality maintained within the entire system. Microbial levels measured within a cistern system are reliable indicators of water quality and of deteriorations that may give rise to offensive odors and tastes. The number of microorganisms commonly found within most contemporary cistern systems is usually lower than surrounding surface waters but these microbial levels may still be unacceptable for many alternative uses. Our laboratory is studying the bacterial populations growing and residing within cistern systems. During periods of rainfall collection and heavy usage, the microbial populations of single-chamber cistern systems do not decrease significantly during subsequent storage (self-purify). The storage of rain water in cistern systems may actually.be conducive to the growth of certain bacterial strains in numbers beyond those found in natural water sources. Our studies have shown that certain types of maintenance of individual, single-chamber catchment systems may actually increase the levels of certain microbial strains when compared to similar systems receiving no.treatment at all. More work is required to identify those parameters necessary for the proper storage and maintenance of high quality cistern water.

Section 3: Catchment and Storage System Designs

Paper 3.1

Proposal For Disseminating Ferrocement Rainwater Tank Technology In The Province Of Capiz The Philippines

Lee Kam Wing
International Development Research Centre (Canada), Singapore

Adhityan Appan
Nanyang Technological University, Singapore

Abstract

Ferrocement has been used as the sole building material in the, construction of 30 rainwater cisterns which constitute the pilot project for introducing rainwater catchment systems in the Province of Capiz. These tanks which were built in three localized areas have been successfully tested for their structural stability and their use has been found to be socially acceptable. The main objectives of the current proposal are to disseminate the acquired ferrocement technology to communities throughout Capiz and to extend the number of, tanks by a further 540. Selected members of the target communities will be trained and communication materials will be designed, tested and produced to support the dissemination activities. A revolving fund w:.ll provide loans to families who want to build tanks but do not have the resources to purchase the construction material required. Health education and communication organization elements will also be built into the project activities to ensure that the ferrocement tanks will have the desired impact in improving the health of the communities and that the technology is fully adopted through a participatory approach by members of various communities.

Paper 3.2

Fabridam Engineering And Its Application In Taiwan

Mao-Sheng Chen,
Ministry of Economic Affairs, Department of Water Resources R.O.C.

Chie-Chien Yeh, Jeffery, Tseng
Taiwan Provincial Water Conserancy Bureau R.O.C.

Abstract

in Taiwan, with unevenly distributed abundant annual rainfall and the steep slope of rivers rushing the rain water flow in rapid speed to the sea, fabridam is highly regarded as one of the best suit for storage and diversion of rain water because of its elastic characters of anti-wearing and compaction resistance.

If properly designed using precast method in mesium or small size of canal, fabridam may perhaps be widely and applicably adopted, for its effective (unique) function of auto-operation which will save more labour cost and fit for economical considerations. The Following papers is a brief description on fabridam engineering proposed to be discussing.

Paper 3.3

Hong-Lo Transbasin Rainwater Harvesting Works For The Cheng-Kung Reservoir In Penghu

Li-Jen Wen
Council of Agriculture, R.O.C.

Abstract

The Penghu Pescadores located in the west of Taiwan Proper are scarce in' water. The annual precipitation is only about 1,000 mm which is much less than the measured evaporation of 1,800 mm. The water supply there entirely relies on the surface runoff and groundwater. In the dry year, the domestic water supply entirely depends on the groundwater even up to 100% as most of the reservoirs dry up.

Due to lack of geological and meteorological data, hydrologic analysis was extremely; difficult for planning reservoirs especially in the early stage of development. At present, there are five surface-water reservoirs and one underground reservoir with a total effective capacity of 3.9 million cubic meters, of which the Chengkung Reservoir with a capacity of 1.04 million cubic meters, is selected for study.

This paper is to review the hydrologic analysis of the Chengkung Reservoir and to illustrate its transbasin rainwater harvesting system which was completed in the recent year. It is emphasized that continued efforts on collection of geological and hydrological data are to be made for application of the improved methodology in hydrological analysis for planning cisterns on the water-scarcity off-shore islands.

Paper 3.4

Solar Electricity in Rain Water Cistern System

Mitsuo Ide Takashi Yoshida & Akira Higuchi
Yoshida Iron-work Co., Ltd.

Abstract

Water is the origin of life and precious resources to us. For the purpose of getting water, communities were composed, farming managed, and manufacturing done. And stable supply of water has helped progress of agricultural techniques, development of industrial economy, and improvement and conversion of industrial structures.

In order to get water resources, we can make the following statements.

  1. River water 
  2. Water from lakes, marshes, and reservoirs  
  3. Rain water 
  4. Water from underground and spring  
  5. Reutilization of water 
  6. Replacing sea water to fresh water, etc.

In order to get water resources in the isolated islands and the top of depth of mountains, utilization of rain water and spring water is easy and economical.

We had investigated and studied to get and stabilize the supply of rain water at the isolated islands of Tokai district in Japan. Besides we devised an apparatus by solar energy .(not by commercial energy) available for the isolated islands. The outline is following:

  1. Quantity and quality of rain water  
  2. Collecting works of rain water 
  3. Solar cells and pump facilities  
  4. Water supply apparatus 
  5. Sterilizer

Paper 3.5

Investigation Into Feasibility Of Usage For Domestic Use Of Collected Rain Water From Open Areas In Urban Regions In Japan

Tadafusa Uchida
Shimizu Corporation, Japan

Abstract

The purpose of this study is to examine the feasibility of collecting rain water for reuse not only from roofs, but also open areas, such as park and public lands. I examined the recovery rate and quality of collected rain water through the use of permeable test pieces representing several types of ground compositions.

The results are as follows:

  1. The recovery rate of collected rain water ranges from 40-70% of the total rainfall during the course of one year and these values depend upon the compositions of the test pieces. 
  2. The quality of collected rain water from non-fertilized test pieces satisfies the Japanese flush water requirements for toilets, and it can be used for a wide variety of purposes, including sprinkler systems. 
  3. The collected rain water from fertilized test pieces contains a high concentration of organic and inorganic substances during the first stages., so its reuse must be restricted to plant cultivation.

However, during the last stages, its quality is almost equal to that of non-fertilized test pieces, so it could be used for a wide variety of purposes.

Paper 3.6

Modernization Of Rain Water Cistern System In Tokyo, Japan

Masami Ichikawa
Tsukuba University, Japan

Introduction

Generally speaking, Japanese islands are plentiful in annual precipitation about 1,600 mm in average, however, annual precipitation is different from place to place and from time to time. Small islands located in the southern part of Tokyo such as Izu islands and Ogasawara islands, there are primitive rain water cistern such as Toshima, Shikine-jima, Hachijo-jima and Aogashima.

However, Tokyo Metropolitan area are modernized in' architectures, cultures and so on especially after the World War II. Many tall buildings are characterized and low with large roofs buildings such as Shin-Kokugi-Kan, Tokyo Dome and etc. in Tokyo.

I would like to explain about the water resources for miscellaneous uses to collect the low and large roofs buildings with the modernized rain water cistern systems in Tokyo.

Paper 3.7

Ground Tanks In Urban Or Rural Settings; The Answer To Water Crisis.

Eluderio S.Salvo
Development of Environmental System, Inc., Philippines

Abstract

The Philippines is a tropical country situated approximately between latitudes 5° and 20°, north of the equator and longitudes 117° and 126°. This island is annually visited by an average of 30 typhoons dumping an average of 2500 mm of r ins. This large amount of rainfall, however, is not evenly distributed throughout the year thus causing long periods of wet and dry months

Analyses of the annual distribution of rainfall shows that during the period from January to June, the rainfall is about 31% of the annual average while from July to December tuber, the rainfall is about 69% of the annual average.

It is to the problem of water crisis brought about by the long dry, spell that. the use of around tanks is addressed. It can be concluded that rain water recovery through the use of ground tanks is an economical method which can be utilized in urban as well as rural water supply systems. Furthermore, ground tanks will also help in minimizing the flooding problem accompanying intense rainfall.

Paper 3.8

Store and Utilization of Rainwater with Tameike Cistern System at Rural Areas in Northeast Thailand

Naoki Utsunomiya and Isao Minami
Kyoto University, Japan

Abstract

In northeast Thailand, 10 tameikes, designed to store rainwater which is catched at paddyfield, were constructed at two villages where they often suffer from, drought damage under rainfed condition. Field data on the ability of tameike pond t conserve rainwater and the possibility of the rainwater utilization for agricultural production were collected.

It was shown that rainwater was efficiently catched and stored with tameike system in rainfed farming areas. Every pond was filled with rainwater flowed from paddyfields during wet season and the rainwater could be conserved even under dry season condition. The stored rainwater seems to have the ability not only to alleviate drought damage but also of desalinization.

Rice cultivation has not 'been affected y dry spell caused by erratic rainfall because the stored rainwater could decrease the damage. In addition, horticultural crops rowing and fish raising were promoted owing to the available water all seasons. Although the benefits areas of the' rainwater for these crops or fish cultivation were confined, 'the amount of their productions was enough to meet self-sufficiency. In some cases their products seem to have a potential to increase income.

These suggests that tameike system is an effective measure which develops rural life in small scale with utilization of rainwater in rainfed areas. This system is more adaptable to improve the subsistence agriculture. The avoidance of the drought and increased the agro-aquaculture due to the stored rain water may increase the standard of living in the village.

Paper 3.9

Extending the Limits of Rubber Dam (Sumigate) Technology

Yoshiomi Tsuji, Ichiro Maruyama, Haruhiko Matsuoka, Kazutoyo Yamada & Katsuya Sakaguchi
Sumitomo Electric Industries, Japan

Abstract

Sumigate is a inflatable and deflatable rubberized fabric+dam (rubber dam), Which consists of, a rubberized fabric tube, operation equipments and pipings. It is inflated by air or water and used for various applications, such as, irrigation, water supply, tidal barrier; etc. because of its many features, namely reliable deflation, easy and quick installation, low cost, excellent durability, and easy operation and maintenance. We have installed about 1200 rubber dams (most less than 3 m high) for mainly irrigation since 1966.

We developed materials for higher rubber dam full automatic operation., system actuated by solar battery, and special cushioning technique and have installed the 5m high experimental rubber dam in 1982 in cooperation with the New 'Energy Foundation and the Electric Power Development Co.

After ten (10) years observation since the installation, it has no damage and it has become clear that our large Sumigate is operating effectively as an diversion dam even in the upriver:

Moreover as the number of rubber dams increased, their: reliability was revaluated through practical demonstration. In 1990 the Japanese Ministry of Constriction has. installed the first actual use high dam(Inou river: 4.71 m H * 24 m L) for irrigation and tidal barrier, exceeding the construction regulations, that prohibited the use of higher rubber dams than 3 m high dams, and the Electric Power Development Co. starts to install the highest dam (Kurotani river: 6 m H * 34.5 m L) for small hydropower diversion dam this year.

This paper describes the current status and future potential of the inflatable rubber dam in Japan through the development procedure of a higher rubber dam.

Paper 3.10

Storage of Rainwater and Snow-water in Southeast Coastal Districts of China and Scattering Purification Treatment of Drinking Water

Zhang Sunwei
Hangzhou University, China

Abstract

On the premise that the evaluation is made on the utility value of rainwater and snow-water used as drinking water by residents in the southeast coastal districts of China, this paper illustrates the purification treatment of drinking water which the residents there carry on in their scattering households.

Section 4: Hydrological Data and Analysis

Paper 4.1

Test Of Watershed Acidification Models Responses To Rainfall Intensity

Fi-John Chang
Department of Agricultural Engineering, National Taiwan University

Abstract

Mathematical models are useful in improving our understand- ing of various processes and predicting the response in freshwater chemistry to changes in the deposition. A general weakness in models of the effects of acid deposition is that the models have not been tested sufficiently against observation. An alternative way to assess the applicability of models is to perform hypothesis test. Consequently, a hypothsis--increasing rainfall intensity will increase outflow hydrogen concentration--was tested with two well known watershed acidification models, the ILWAS and Birkenes models.

The ILWAS models confirms the hypothesis, while the Birkenes model does not produce the same conclusion. This is probably due to the simplicity of the hydrologic submodel of the Birkenes model and its assumption of constancy of the cation exchange capacity. The result of test the ILWAS model for the hypothsis show that it is a useful tool in the investigation of watershed acidification. This process-oriented model provides the essential insight to make predictive assessment of the effect of surface and subsurface water acidification under different loading.

Paper 4.2

Application The Bayesian Approach To Hydrologic Sampling Theory For The Cho-Shut River In Taiwan

Ming-Te Liang
National Taiwan Ocean University, R.O.C.

Abstract

The principal aim of this article is to study the Bayesian approach applied to the statistical distribution of the annual maximum flow of the Cho-Shui river in Taiwan. An important result obtained from investigation is the without and with prior information to the Cho-Shui river, the posterior distributions are respectively N(3.721,0.100) and N(3.055,0.081).

Paper 4.3

Envelope Curves for Extreme Flood Events in SW Iran

Ahang Kowsar, Mohammad Hossein Borhan
Research Institute of Forests and Rangelands, Iran

Mohammad Reza Khooban
Fars Water Authority, Iran

Abstract

Water shortage in dry areas is the most limiting factor in their growth, even in their existence. Many civilization have vanished because their water resources had exhausted. Preparation of the systems which harness and conserve floodwaters in unusual rainfall events is one way to replenish the badly depleted aquifers, as well as to produce and preserve food, feed, fiber and fuel for the lean years. Prediction of the runoff potential of watersheds in extreme events is a rather conservative method for estimation of the size of floodwater spreading systems and artificial recharge facilities. However, long time, continuous hydrological data required to base the pred:.ctions on are lacking for most of the desert watersheds in Iran. Therefore, it is necessary to resort to empiricism for prediction of runoff events. Development of envelope curves for regions with a few gauged watersheds facilitates reasonable estimation of the maximum probable peaks for ungauged basins in the same area.

A total of 36 data points of the deluge of Dec. 1986 were used to derive envelope curves for the Mond, Helleh, Zohreh and Shiraz basins. Euation of the form Q=C+B/A, in which Q is the peak flow in ls-1 km-2, A is the area of the basin in km2 and C and B are constants, best describe the overall performance of the basins. However, other equation farms might better match some individual watersheds in the region.

Paper 4.4

A Coupled Model Of Overland Flow, Soil Water Variation And Groundwater Regime In North-China Semi-Arid Plain

Huan-yen Loo and Dei-sun Lu
Shanghai Tongji University, China

Abstract

Rain water, soil water and groundwater are interconnected as an intrinsic system. Differential equations of water movement for individual unit of the system have been solved separately but linked together by regarding their common interfaces, namely the surface- water/soil-water and the soil-water/ground-water, as internal boundary conditions. The soil water variation is a controlling factor in transmitting rain water into groundwater, an one dimensional equation for soil water variation is then solved first using finite analysis method with a prescribed initial soil water content above a variable groundwater level during either precipitation or evaporation. If the precipitation intensity is higher than the soil infiltration rate, a depth-averaged two dimensional solution for the overland flow is approximated by a power series method to see if both the duration and the depth of ponding water are suitable for crop growth, or otherwise a three dimensional groundwater regime due to adjusting the pumping scheme for the agricultural and/or the municipal use is calculated by boundary element method in order to make an optimal management of the water circulation. Such a computational process is repeated until minimizing the water-logging, preventing the soil salinity and balancing the water resource are reached to an expected situation.

For the North-China semi-arid plain, model studies show that the optimal groundwater depth for an excess.rain season is about 3.5 m at the up-plain, but 5.0 m at the down-plain area, especially, near the shore line, the groundwater level must further be lowered owing to both the slow infiltration rate of the fine soil and the existence of saline water unable for plant growth.

Paper 4.5

Characteristics Of Maximum Daily,Rainfall On Vietnam And It's Influence On Soil Erosion

Nguyen Van Tuan, Le Van Lan
Hanoi University, Vietnam

Abstract

Vietnam is the Tropical country, so its rainfall is high and its periods of sunlight are long. It's rainfall, especially, daily rainfall is the main cause of the flood and soil erosion. Studies of maximum daily rainfall serve as a base estimate flood and soil erosion.

This article expresses the results of the studies undertaken for many years about rainfall and soil erosion all over Vietnam Consisting of more then 1000 rainfall station with ten years data and data of 40 erosion tanks at Tay Nguyen-central part of Vietnam and at Vinh Phu province. Also this article mentions the following ideas:

  1. The causes of flood Rain in Vietnam 
  2. Characteristics of an annual Rainfall and maximum daily Rainfall, it's spatial-duration variation. 
  3. Methods for calculating the maximum daily Rainfall.  
  4. Influence of Rainfall on soil erosion and methods of soil erosion estimation based on maximum daily Rainfall data. Characteristics of maximum daily rainfall on Vietnam and it's influence on soil erosion

The main causes of flood Rain in Vietnam, Vietnam is the Tropical monsoon country, so that it's rainfall is very high. Many Researchers (5,6,7,9) show two main factors that cause flood Rain in Vietnam. They are:

  • The action of world air masses (General circulation of air masses and 
  • Geography.

Section 5: Cistern Management and Operation Guidelines

Paper 5.1

Dynamic Programming of Rain Water Catchment

Richard J. Heggen
University of New Mexico, USA

Abstract

Rain water catchment has four engineering aspects: design, implementation, construction and operation. Routine design matches capacity with demand. Improvements in financial and educational infrastructure further the regional-scale implementation. Material and technique development make construction more appropriate. The weak link in the engineering process is that of operation, managing the catchment to maximize benefit.

Dynamic programming, a tool long used in reservoir operational studies, reveals how a catchment can be managed (when to draw,, when to conserve) to minimize the penalties associated with water shortage. Penalties can be defined in arbitrary terms, relatively or absolutely. Demands can be historic or synthetic, with or without trend, seasonality or random fluctuation. Rainfall can be likewise actual or synthetic. As a deductive tool, dynamic programming reveals the optimal mode of catchment operation for any, scenario of supply and demand. As an inductive agent, the analyst may reduce that knowledge to rules for real-time decision making.

A New Mexico catchment system is dynamically evaluated. A seven year rainfall record is employed with logistic, exponential and unit price penalty schedules.

Paper 5.2

Development of Guidelines for Rainwater Cistern Systems in Nova Scotia

Richard S. Scott, Donald H. Waller
University of Nova Scotia.

Abstract

Rainwater cistern systems have been in use in Nova Scotia for more than 50 years as an acceptable alternative drinking water source where groundwater supplies are inadequate or are contaminated by gypsum, arsenic, uranium, iron and manganese, road salt, or sea water intrusion. In recognition of its importance, the Nova Scotia Department of Health published guidelines in 1982 for system construction and operation. The source material for this document originated from outside the province and for the most part was not directly applicable to the region. For this reason, research was initiated by the Centre for Water Resources Studies at the Technical University of Nova Scotia and later conducted jointly by the Centre and the Nova Scotia Department of Health on Nova Scotian systems to develop more comprehensive guidelines with the local climate in mind. This paper discusses the various components of a rainwater cistern system and presents recommendations for system design and system operation and maintenance in Nova Scotia.

Paper 5.3

Water Operation On Tameike In Toban Region In Japan: A Rain Water Catchment System

Kunihiko Kitamura
Ishikawa agricultural college Japan

Isao Minami
Kyoto university, Japan

Abstract

Toban region has been irrigated mainly by tameikes which are operated mostly intensively. The rules of operation have been formed by farmers experience for hundreds of year. They are reasonable and instructive. So the author had investigated about the tameike operation in the Toban irrigation area for several years and got the following results.

1) Tameikes are classified into four types by their function, mother-ike, daughter-ike, independent-ike and collecting-ike. They compose a water system combining the function of each type of ike. Features of the system are much related to the topography. For example, in the flat belt, a close combination between mother-ike and daughter-ike Is obviously seen. In the mountainous belt, each independent-ike irrigates its own area independently. And each collecting-ike exclusively supplies its daughter-ikes. In the middle belt, the characteristics of both flat and mountainous belt are seen.

2) A standard storage level is set at each tameike. Usually, it is decided at a level of half to one-third of its full depth. When the storage of daughter-ike decreases to this level before the middle of September, the mother-ike supplies her during the night, from 20 to 6 o'clock in the next morning.

3) A ditch-tender selected among farmers exclusively operates the tameike and distributes the water to each plot of field systematically. His standard working time is usually 12 hours a day, from 6 to 18 o'clock. When it rains, he stops release of tameike to conserve its storage.

Paper 5.4

Optimization Of Ground Catchments To Maximize Rain Water Collection In South Africa

Cecil Chibi

Abstract

About 40% of South Africa suffers semi-arid id to arid conditions with annual rain varying up to 200 mm. People staying in these areas are largely served by ground water through bore holes for their water needs. Typically the water is rich in dissolved iron or has an unacceptably high content of salt. The settlements in these areas, as is often the case, are sparsely distributed making it costly to import water. This means that the next practical and appropriate source to develop is rain water which is at the moment only exploited limitedly.

The importance of rain water as an alternative source have already been well documented elsewhere (e.g. Waller 1989) and will hence been assumed in this paper.

In the past the development of rain water catchment systems in South Africa has centred largely in the optimization of roof catchment Systems. Significant breakthroughs have been realized in work on water storage tanks. However, little has been done to explore the potential for ground catchment systems.,

This paper reports on work done by the Division of Water Technology (CSIR) to evaluate ground catchments that have been treated with four locally available materials viz a tar product, paraffin wax graded sand and gravel and gravel covered sheeting. To date the gravel-covered sheeting method. ha shown the greatest promise for use because the catchment plots are easy to prepare, the media affordable and most importantly deliver a reasonably good quality water.

Paper 5.5

Optimal Cistern Size For Hydroponic Greenhouse Operation

John W. Brown
University of Guam Mangilao, USA

PingSun Leung
University of Hawaii USA

Abstract

Hydroponic farms are starting to be adopted in the American Pacific Island for a variety of reasons. There are currently hydroponic operations in Hawaii, American Samoa, Guam and the Marshall Islands. Many of these operations use cistern stored rainwater, because of a lark of reliable water supplies, or because of the quality of available water supplies is unsuitable for hydroponic culture. Many of these sites are prone to periodic droughts. Thus, sizing. the cistern is of vital importance to the economic viability of the operation. The cost of construction of an oversized cistern is an unnecessary expense, while the construction of an inadequate cistern exposes the operation to a higher risk of a loss of crops.

This paper develops a simple methodology for the optimal sizing of cisterns given the rainfall history of the site, the water use of the hydroponic system and the costs of construction. Specific examples are developed for Guam and the Marshall Islands.

Section 6: Socioeconomic Aspects and Cost Analysis

Paper 6.1

Economics of Flood Irrigated Cereal Hay Production

Ahang Kowsar & Esmail Rahbar
Research Institute of Forests and Rangelands, Iran

Abstract

Insufficient rainfall makes dry-farming an undependable method of food and feed production in many parts of Iran. Moreover, groundwater (GW) mining for irrigation of crop is threatening the very existence of the desert dwellers. Therefore, augmentation and conservation of GW for later, wise utilization holds the key to the prosperity of the future generations. Flood-water spreading (FWS) is a very easy and economical means of crop production in the arid and semi-arid areas

Flood irrigation of wheat and hay in the e Joonegan County, Mamassani (mean annual precipitation, MAP- 579mm) in 500 ha of rainfed wheatfields during the 1980-81 growing season resulted in substantial gains in grain and hay production. The grain yield on a 40 ha tract ranged 1214-1685 kg ha-1. The highest grain yield in control farms was 700 kg ha-1. T'he forage yield ranged from 1500 kg hasup-1 for Medicago scutellata Mill. to 300 k ha-1 for Trifolium alexand it num L. Improved yield for wheat of up o 3200 kg ha-1 have been reported of up to 4300 kg ha-1, and for medic of up to 3200 kg ha-1 have been reported for more recent years. Disregarding the extra benefits accrued through artificial recharge (AR) and flood mitigation (FM), the benefit to cost ratio (C) was 5.1.

A 650 ha FWS system was constructed in the e SE corner of the Gareh Bygone Plain (MAP=150mm) for barley reduction. The grain yield of individual farms ranged 700-2000 kg ha.-1 with the mean of 1400 kg ha-l in the 1984-85 crop season. The highest grain yield of control plots was 700 kg ha-1, Disregarding the extra benefits accrued through Area of GW,. FM, and forage production in the fallow period, the BCR compounded yearly at 15% for 10 years was 2.2. Should the real cost of irrigated grain and hay production be considered, the BCR would be larger than the reported figures.

Paper 6.2

Opportunities For Rainwater Cistern Systems In Rural Economic Development

Donna J. Lee Ping Sun Leung Yu-Si Fok
Univ. of Hawaii, USA

Show Chyuan Chu
National Taiwan Ocean University Taiwan, ROC.

Abstract

Lack of sufficient supplies of safe drinking water plagues the development of rural communities. Selecting an appropriate system to supplement freshwater supplies depends on economic, social, and institutional components of the community. Rain water cistern systems are recognized as an effective, alternative means for providing safe drinking water to rural areas worldwide. Rural rainwater cistern systems are generally government initiated. Successful implementation, however, requires both community acceptance and community cooperation in the construction and use of the new systems. This paper examines the relationship between rural water supply systems and stages of economic development, and suggests opportunities for implementing rainwater cistern systems to meet rural development goals in Asian-Pacific countries.

Paper 6.3

A Method Of Economic Appraisal Of Rain Water Cistern Systems As Applied To High-Rise Buildings

Dr.Adhityan Appan
Nanyang, Technological University, Singapore

Abstract

The revival of Rain Water Cistern Systems (RWCS) and their adaptability for application in high-rise buildings are of relatively recent origin. A p::ime mover for acceptance of RWCS in high-rise buildings by both society and any water authority is to establish the economic viability of such systems. In this paper, the capital,and operating costs fcr an RWCS in high-rise buildings are considered. The benefits are limited to savings in water utilized and the deferring of capital-intensive schemes due to this saving. The methodology used for the latter is the "Unit Cost of Leakage" approach. A typical case study is costed in the Singapore context to establish the net benefits that can be reaped by adopting such RWCS in high-rise buildings.

Paper 6.4

Derivation Of Some Opportunity Cost Analysis Solutions For Economically Optimal Tank And Catchment Sizes In Rainwater Collection System Design

Carmelo M. Gendrano
Tulungan sa Tubigan Foundation, Inc, Philippines

I. For Constant Catchment Area Size

Assuming an RWCS with known catchment area A, constant and known demand D, and operating under known rainfall pattern and rainfall-runoff relation:

Paper 6.5

Benefits, Favourable Situations, And Cost Optimization Of Rainwater Harvesting Systems

Dr.George Michaelides
Nicosia, Cyprus

Abstract

The benefits of rainwater harvesting from house roofs for domestic water supply are: the rainwater supply is next to the users house; it is compatible with the approach of "user participation" and "local resources" technology; its technical simplicity; it promotes water conservation; schemes are suitable for construction in stages and in conditions of uncertain initial data on water use; no land requirements; and, operation and maintenance are simple. Favourable situations for the development of rainwater harvesting systems are: dispersed settlements; existing house roofs; and high average rainfall (reduced catchment area required) and little seasonal or annual variability in rainfall (reduced storage volumes required) result in relatively low total costs. The cost of rainwater harvesting systems can be optimized through appropriate planning, design and construction of roof catchments, storage techniques, storage size, use of water. Costs can be saved by the use of unreinforced storage tanks, durable tanks and by planning storage into construction of new buildings.

Paper 6.6

Rainwater Harvesting Costs And Benefits

Sampson K. Agodzo
University of Science and Technology

Abstract

In this paper, it is argued that rainwater as an important alternative source of community water supply cannot only be viewed in terms of cost justification but also in terms of such unquantifiable benefit: as time savings and improved hygiene. An attempt has been made to provide guidelines for cost calculations of rainwater harvesting projects, bearing in mind that when resource constraints are applied to the selection of an appropriate community water supply technology, it may turn out that improvement of traditional sources is the only feasible option.

Paper 6.7

Financially Sustainable Gravity Fed Water Catchment Schemes In Kenya “Following A New Approach”

Janet K. Lugonzo-Campbell
Canadian Hunger Foundation,

Introduction

In 1982, the Canadian Hunger Foundation (CHF) carried out a study of village water projects in Kenya to find out why they had such a high failure rate. Many of the projects studied had received donations from development agencies or NGOs which were used for the purchase and installation of materials. Ho ever, without a sound institutional framework, water would flow only for a short time much to the bewilderment of the donor, who would of understand why the project had 'failed'. The result would frequently be an evaluation seeking technical flaws that excludes 'an assessment of the institutional aspects. Repairs or modifications would then be carried out for the technical flaws, but water would still not flow continuously. Eventually, the donor would be come disillusioned and finally resign from the project.

The symptoms of institutional inadequacy were found to be

  • Poor Management skills 
  • Little or no organisational structure 
  • Lack of maintenance skills 
  • Absence of a sound financial plan of regular income and of administrative controls 
  • Absence of a sense of ownership of the water project by the community 
  • Ignorance of the skills and resources required to run a water project 
  • A 'charity' relationship between funding partner and the community groups

It was clear that the institutional requirements of village water projects had not received enough attention. All parties concerned had grossly underestimated what is required f r such projects to be successful and self-sustaining. It was apparent that a new approach was required. Thus the CHF embarked on the development of a new approach and used it to support a number of projects. In the case of the first CHF assisted project, the CHF commenced in 1984 and withdrew in 1987. By 1989, the group had a healthy bank balance, expanded their project by 100% and had built their own offices. It now serves as a model for other project development all over Kenya. It is the NGO which participated in the community's project not the other way round.

Section 7: Agricultural Uses of Cistern Water

Paper 7.1

Hung-Lou Trans-Basin Diversion Project In Penghu Area

Chun-Yen Chien, Cheng-Nan Tsay, J a -Chyun Wang
Water Conservancy Bureau (TPWCB, Taiwan, R.O.C.

Abstract

Penghu Archipelago is located in southeast part of Taiwan Strait. The average annual rainfall is 1,'013 mm which is no more than one half of that in Taiwan Area. In addition, evaporation is as high as nearly 1.8 times of its average ,annual rainfall. Since there are no high mountain and forestry in the area, most of the rainfall either infiltrates or runs off to the sea immediately. The supply of fresh water is in great shortage all year round for Penghu area. To solve the problem, the utilization efficiency of rainfall should be promoted. Cheng-Kung reservoir has usually failed to' be filled up owing to insufficient inflow. In order to increase the inflow, an interception wall and conveying channel were built near Hung-Lou village to divert the runoff from adjacent watershed to the reservoir. As a result, the annual water supply has increased 20 %.

Paper 7.2

Rainwater, Water Table And Soil Moisture In A Hillslope

Jose de Oliveira Leite & Antonio Cadima Zevallos
Cacao Research Centre, Brazil.

Abstract

The objective of this work was to stud y the relationships between the rainfall, the water table and the soil moisture regimen in a hillslope planted with cacao. These parameters were measured daily during 270 days.

The water table was observed in a set o 5 wells located in a contour line of the hillside. Beside the middle well two sets of tensiometers were installed at 15, 30, 60, 90 and 135 cm depths. Also, the soil composition, density of aggregates and moisture equivalent were measured. It was found that, horizontally, the soil profile can be divided into three zones: the op zone (from 15 to 30 cm depth), not submissive to the water table rise under rainy conditions. This zone presents an average soil moisture content of 0.48 (cm3/cm3). In the middle zone (30.- 90 cm), the average moisture content ranges from 0,50 to 0,55 f the water table. is below or above 4m depth, respectively, and th bottom zone, below 90 cm, is more submissive to that saturation although its moisture content is not statically different than o the upper zone. The peculiarity of the middle zone, which is composed of B21 and B22 horizons, is associated with its high clay content. Also this zone represents a water reservoir to the cacao' tree. In general, the results suggested that the water table height, associated with the rainfall conditions, controls the moisture content in the whole soil profile. However at the 30 - 90 cm depth, the transpiration flow of the cacao tree may also play an important role in the soil moisture regimen.

Paper 7.3

Scientific Method of Kanat's Artificial Recharge, With Examples of the Efficiency of the Methods Describe in Iran

Abdolkarim Behnia
Chamran University, Iran

Abstract

In this research different methods causing kanat's artificial recharge are identified classified, and introduced. The results of their application have been described in Iran. These methods consist of five ways of surface recharge and three ways of underground recharge of aquifers. The five surface recharge methods as follow: construction of vast artificial pool with specific artificial pond; storage of water in the area above the mother well; Construction of earth dams at the floodway s around kanats; The expansion of the vegetation of soil and making the strips along the tarekar of kanats. Three methods of artificial groundwater are artificial recharge by well, by joining the deep wells and kanats and lowering the ground water level. Based n the local research among the eight different methods presented for the artificial recharge of kanats, the construction of recharge well is recognized to be the cheapest and the easiest of all and is recommended as an effective method for increasing kanats discharges.

Section 8: Irrigation and Uses of Water

Paper 8.1

Rainwater Catchment For Future Generations; Small Reservoir Irrigation Scheme In The Philippines

Rodrigo N. De Guzman
National Irrigation Administration, Philippines

Background

The Philippine Archipelago, a country of 61 million inhabitants lies entirely within the humid tropics between latitudes 5° and 20°N longitudes 117° and 127°. Micro climate within the islands are largely influenced by altitude. (most islands have narrow coastal plains surrounding mountain ranges with height from 500 - 2,900 m) and the direction of prevailing air stream. the latter influences seasonal variation in climate, in particular the rainfall distribution pattern.

Annual rainfall is from 1,500 to 4,200 mm. In most lowland areas average rainfall is generally adequate for a single crop in the rainy (wet)season. However, rainfall is often not evenly distributed and dry spells frequently necessitate supplementary water supplies. Unfortunately, the country lies in an area recognized. as having the greatest frequency of tropical typhoons in the world. Between 1948 and 1988 an average of tropical typhoons were recorded annually mostly in the months of June to December, with the highest monthly frequencies (more than three) in July, August and September.

Water resources development in the Philippines for irrigation, power, domestic water supply, and industrial purposes involves a variety of types, from simple diversion to huge reservoirs, to shallow wells, to deepwells, and to rainwater conservation through storage.

This paper presents a case study of rainwater cistern system or rainwater catchment for irrigation, flood control and soil and water conservation for future generations.

Paper 8.2

Rain Water Catchment Ponds For Irrigation In Taoyuan And Shihnen Districts Taiwan

Wen-Jung Hu & Ching-Ho Ku
Council of Agriculture, Executive Yuan, ROC

Abstract

Both the Taoyuan and Shihmen Canals take water from the Shihmen Dam to irrigate farm lands amounting to 37,00 h .in the Taoyuan and Hsinchu counties of northern Taiwan. According he definite plan of the Shihmen Dam Project and the actual irrigatio operation, the dam can only provides a portion or about 50%-60% f the total amount of irrigation water, and the rest .s to be supplied by the regulation of irrigation farm ponds and the flow catch d by local diversion weirs. The topographic conditions and soil types in these areas are generally suitable for farm pond construction an operation. Totally 686 farm ponds with capacity of 45,160,000m ere constructed as rain water catchment facitities and have Dean operated by the Irrigation Associations (IA)for irrigation for a long time.

Recently, owing to the Environmental and socio-economic changes, the farm land has decreased because f industrialization and urbanization. Review on the capacity o he farm ponds was, therefore, considered necessary so as to keep ac with the reduction of irrigation area. A mathematical model based on the theory of linear programming has been studied for review ing and planning to determine the necessary capacity of the farm ponds. By computer manipulation of the linear programming, the results appeared that the farm ponds still play a very important role for irrigation in this area. If the farm ponds provide 35% or r.10 more of the irrigation water, the total capacity of the farm ponds s hould be reduced by reducing the farm lands. As the result of the s tudy, the purpose of effective utilization of land and water resources in Shihmen Dam service area can be realized.

Paper 8.3

The Merits Of Smoothing Irrigation Furrows To Improve The Uniformity And Reduce The Total Application Of Irrigation Water

Ebrahim Hejrati
Agriculture Head Office of Eastern Aearbaijan, Iran

Summary

The infiltration rate changes with time. It is a fairly high value when the soil is first wetted, then it quickly decreases to a much smaller, but stable, rate known as the basic infiltration rate. There are many factors which will change the initial part of the infiltration curve, the two major factors are the soil moisture content before irrigating and the surface roughness. Smoothing the roughness in a furrow acts to speed up the furrow advance and the recession so that for a given' inflow time the opportunity time remains nearly constant. The accumulated infiltration is a function of the opportunity time and the infiltration rate curve for the particular soil. The uniformity of the water which is infiltrated into a soil is dependent on the uniformity of the opportunity time along the length of the furrow being irrigated.

The data reported were collected during the third irrigation in a field planted to corn on a silty loam soil in Eastern Nabras. Two basic ditching treatments, using a conventional ditcher and using a Hawkins ditcher, were each compared with and without an additional smoothing operation.

Smoothing the furrows increased the uniformity coefficients for the opportunity times along the furrow in both ditching methods. No test of significance was conducted on the data due to the lack of replications.

Reducing the roughness coefficient by smoothing the furrows speeded up the furrow stream advance which would have allowed a shorter set time, thereby reducing the total application of water. The objective of applying 2 inches of water could have been achieved if the well had been shut off: sooner. This would not have adversely affected the uniformity of water application.

Section 9: Alternative Uses of Cistern Water

Paper 9.1

Multiobjective Rain Water Cistern Systems

Show-Chyuan Chu
National Taiwan Ocean University, Keelung, Republic of China.

Yu-Si Fok
University of Hawaii at Manoa, U.S.A.

Abstract

Rain water cistern systems can serve multiobjectives. Although they are traditionally used for domestic water supply, however they have been used for other purposes. From an economic view point, if a rain water cistern system (RWCS) can serve multiobjective uses, it could afford a higher initial and operation/maintenance costs. Therefore, planners of rain water cistern systems should seek multiobjective uses to enhance the feasibility of their applicability. Examples of :cain water cister systems multiobjective uses are presented in this paper, Readers are encouraged to report their experience related to this subject.

Paper 9.2

The Water Harvesting/Aquaculture Project:PVO/University Collaboration

Alex J. Bocek Kyung H. Yoo & Bryan L. Duncan
Auburn University, Alabama, U.S.A.

Abstract

The Water Harvesting/Aquaculture Project ( P): was a five-year project funded by the U.S. Agency for International Development (USAID). The principal goal was to "improve the quality of rural life in selected developing countries through the introduction of improved technology in ways that would balance local capacity for development with total community needs and potentials."

WHAP involved collaboration with six private and voluntary organizations (PVO's) in 41 countries during: h project period. The project provided technical training and assistance on water harvesting and aquaculture technology to field staff working with local organizations, communities and individuals. Training participants acquired background knowledge. o- :make. preliminary project designs and assessments. Technical ass -stance was provided to those who initiated projects but lacked the kills and knowledge necessary to go beyond preplanning and site assessment.

The paper provides overview of WRAP, and discusses the water harvesting concept and authors' experiences u d r arid and semi-arid conditions.

Paper 9.3

Rainwater Catchment Using Farm Pond in Southwestern Taiwan

Chien. P.W. Yuan, Y.H. & Wan; Y.
Taiwan provincial soil and water conservation Bureau

Abstract

Farm ponds are primarily designed and constructed for storing rain water and providing water supply for the township of Tos-cheng, Yu-Ching, and Nan-Hua in Taiwan county. Te-Liao, and Yen-Tsoinkaohsiung county where water shortage is a serious problem. In the past 20 years, from 1970 to 1990, a -total f 58 farm ponds were constructed with a total volume of 2,745,200 Using farm ponds to collect rainwater is an unique feature in Southwestern Taiwan.

Rivers and streams in Taiwan are short and steep. Water flows swiftly to the ocean. Although the rainfall is abundant, water supply in Taiwan is limited. The average annual rainfall on the island is about 2,510 mm with large spatial variability. Rainwater is a valuable water resource in mudstone are areas with unavailable groundwater resource and insufficient surface water source Since 1965, the Taiwan Procincial Soil and Water Conservation Bureau initiated a policy to construct a lot of farm ponds for storing rain water and supplying water to satisfy people's domestic needs, agriculture and livestock raising. The cost for a pond construction is higher than tap water. However, it is necessary to improve people's living environment, and to upgrade a production. Farm ponds can also control gully erosion and landslide in mudstone areas.

A lot of effort have been spent in conducting reconnaissance survey, planning and design of earth embankment and farm ponds using impermeable mudstone materials So for, no dam failure has been reported. When farm pond is filled with sediments, the sludge has to be dredged out. The sludge has been used o cultivate crops such as dates and guava to increase farmer’s income. This technology has been transferred to local governments to assist in planning and design of more farm ponds and rainwater cats en systems.

Paper 9.4

Water Use Problems In Mudstone Areas Of Southwestern Taiwan

J. F. Hsi.ao & C. H. Wu
Taiwan Provincial Soil Conservation Bureau , Taiwan

Abstract

The hilly areas of southwestern Taiwan is dominated by mudstone. Under normal conditions, these areas have adequate but unevenly distributed rainfall. Many small gullies are found on steep slopes. Mudstone soils are usually shallow and impermeable. Even with abundan, rainfall at times, water shortag problems often occur during dry seasons due to poor water holding capacity. The agricultural water use in these areas is characterized by growing first crop of rice in river valley' and flatland d using rainfed. The field-collected rainwater is used to grow a se and crop of rice from June to October. In recent years, increasing number of farm ponds has been constructed to provide^ water for hill lope orchard farming. Besides irrigation and pest control, purposes the collected water has been used domestically. This paper briefly introduces this water utilization method and its use in a natur al setting.

Paper 9.5

Rain Water Catchment System In Hydraulic Experimental Station

Isao Minami
Kyoto University, Japan

Hiroshi Itagaki
Gifu University, Japan

Abstract

We has developed the rain water resources ya tameike (pond) in the laboratory of water use engineering , Kyoto University. Though we needed much water for the new laboratory of water use engineering at the remote location from Maizuru city, Kyoto Prefecture, the water was not enough to operate hydraulic experiment for 45 students and for researches of water use engineering. After several Years from the construction of new laboratory, though the Maizuru city had constructed new domestic water line with bigger diameter in this area in 1980, the water fee -consumed by hydraulic experiment in the laboratory was very expensive: one'. Then we had introduced the facilities with rain water collection pipe line in underground and a tameike in our experiment station The major items of facilities are as follows. --

  • dimensions of rain water catchment system total area of laboratory 2.5 ha 
  • watershed area of tameike 1.0 ha 
  • rain water collection pipe line in underground side ditch of paved road 150m long an 6 meters width 
  • under ground drain pipe 250m

Paper 9.6

Design Of Coastal Fresh Water Pond For Optimum Use Of Water Resources

C.J. Lai, H.H. Hwung
C Eng-Kung Univ, Taiwan

D.B. Pan
Fifth Division, Industrial Development- Bureau, Taiwan

Introduction

An idea of constructing a coastal fresh water pond system for reclaimed area is reported. This pond utilizes.. a dividing channel, initially designed to isolate the reclaimed l and from the nearby urban area, as the fresh water reservoir. The completed fresh water pond system is composed of (1) Linkage, conveyance and bypass (2) Monitoring & control, MACS and., (3) pond storage, CFPW systems. System design requirement for the pond and consideration are listed.

The MACS is planned to be fully automatic: and performed in both predictive and real-time modes. The linkage system uses two by-pass channels and retain most of the current environmental issues. The pond is designed to have overall storage of 21, x106 M3 and capable for industrial water supply of two months. The overall system is being evaluated in an experimental-station:

Paper 9.7

The Use Of Rain Water For W.C. Flushing In The U.K.

A Fewkes & A Jay
Nottingham Polytechnic United Kingdom

Abstract

The general problem concerns the use of rain water for w.c flushing. In the past there has been no financial incentive for U.K. customers to conserve water because charges were not based upon the volume used. During the next: decade the me tering of domestic supplies is to be introduced and water conse rvation devices are likely to become financially viable. The integ ration of rain water w.c. flushing cisterns into U.K. dwellings and their economic feasibility is evaluated. Finally the reactions of water suppliers, housebuilders and consumers in the U.K. t his method of water conservation are presented and discussed.

Paper 9.8

A Simple Weir for Economical Floodwater Diversion

Ahang Kowsar, Akbar Zargar
Research Institute of Forests and Rangelands, Iran.

Abstract

Diversion dams or weirs sometimes constitute the most expensive and troublesome structures in the design and construction of floodwater spreading (FWS) systems. Many plan for construction of potentially viable FWS systems have bee cancelled in the feasibility stage studies because, on occasions, the expenses involved in the design and construction o a single weir or diversion dam far outweigh the cost of the rest of the project. Thus, justification of the entire project hinges on designing a workable structure at a low cost. Gabion provides a useful material for construction of simple, inexpensive weirs which could be fitted into many designs, and may be. built by unskilled laborers.

Fifteen pieces of 3 0 x 4 0 m, 3 mm diameter galvanized wire netting were used. to construct a.0.60 m high on a 28.0 m wide ephemeral river on a debris cone to diver up to 5m3 s-l of floodwater to a 25 ha FWS system in the Gareh Bygone Plain in, southern Iran. The costs were at least 136 times lower than building a hydraulically efficient, concrete structure having the same capacity.

Although the intake structure behind the weir located on the inside of the river bend, and at a 9° angle to it, no detectable deposition of sediments has--taken-place at this point during 6 years of operation. These hydraulic anomalies deserve further attention.

Paper 9.9

The Catchment Rain Water System Used as Supplemental Water Sources of Cities and Towns

Wei Yu-rui
Institute of Environmental Health & Engineering

Abstract

Catchment rain water used as domestic water has a long history in many areas of china. That is not only major water source in short water areas, but also important supplemental water source in which far from water sources or bad water quality. With consumption increasing rapidly, water resource is deficient day by day. Catchment rain water for additional water sources is more and more paid attention to.

Section 10: Country Reports and Future Outlooks

Paper 10.1

Experience In Rainwater Harvesting-In Tanzania

Mayo A. W.
University of Dar es Salaam

Abstract

This paper discusses a wide range of experiences onpractical aspects of rainwater harvesting in Tanzania. The discussion covers the prospects and difficulties experienced in aspects such as the cost of rainwater cistern systems, the rainwater quality,. the adequacy of rainwater supply and the feasibility of rainwater cistern system in both urban and rural areas in Tanzania. In most of rainwater cistern systems, the quality of rainwater was found to vary widely largely due to the design and construction of the storage tanks, the consumers user habits and flushing system for first rains. The quality was generally found to be insufficient for full domestic use in most of the rainwater cistern systems and the availability of alternative sources of water was found to influence the rainwater consumers' habits

Paper 10.2

Water Of Island In Japan

Isao Minami
Kyoto University, Japan

Kouichi Takeyama
Shimane University, Japan

Abstract

So far the water situation of small islands far from main land of Japan was especially very serious. The water had been developed from rainfall by several traditional methods. But there was no enough studies on suitable apparatus and facility to store that rainfall. Then many islands were very strict in water utilization. Lately Japan government had issued big budget to improve this water shortage in remote islands, and they had developed the water of remote islands introducing various technology and engineering methods.

We would like to show the comparison between old situation and present situation of water resources of remote islands.

Rainfall distribution of island in Japan has big difference between north part and south part. But most serious part is the islands in Seto Inland Sea. Then we had performed field survey on water situation on this area. The smallest island was Uwoshima island and the most developed island was Nakajima island.

(old situation of water in islands)

  1. Rain water cisterns were used on inconvenient parts of islands  
  2. People has clustered in flat: places along seashore 
  3. People has been endured serious shortage of water 
  4. Ground water had been developed, but sometimes salt water was contained.

(present situation of water in islands after development by government)

  1. Ground water was developed by wells and pipe line system were introduced.

Paper 10.3

Utilization Of Rain Water For Domestic Activities In Thaibinh And Nghetinh Provinces In Vietnam

Nghuyen Van Tuan & Le Van Lanh
Hanoi University, Vietnam

I. Physical geological characteries of Nghetinh and Thaibinh provinces in relation with the water supply.

1. Physical geological conditions of Thaibinh province. - Geological position:

Thaibinh is one of the provinces situated near by the sea in Bacbo plain (fig 1). Three sides of it are large rivers: Red River, Luoc River making natural border between Thaibinh and Haihung at the North and Thaibinh and Hanamninh at the South. Its Eastern side faces Biendong sea.

The area of this province is 1495 Km2. Population is about 1,539,500 people with a density of 1022 people/Km2.

Topography of Thaibinh

It is a province in the plain in the Red River estuary. It's Topograph is out by the rivers and streams outside as well as inside: Red River, Luoc River (outside), Trady, Hoa Rivers (inside) and a lot of ponds marshland, lakes. Density of rivers is about 0.25 Km/Km2.

The area of all lakes and marshland is 11044 ha and the lenght of canels is over 45 Km. It's has over 50 Km coast line. It means that salinity intrusion into the land goes throughout the province. So salinity takes place nearly everywhere of the province.

Meteorological characteries:

Thaibinh is one of coastal provinces in the tropical and mosoon zone. It's rainfall is rather high. It often happens together with storms. The rainy season costs for 6 months (May to October) and the rest six months belong to the dry season

Paper 10.4

Rainwater Harvesting Systems For Drinking Water Supply In China

Ling Bo
Inst. of Environmental Health & Engineering, CAPM, China

Liu Jiayi
The Office of National Patriotic Health Campaign Committee, China

Abstract

Rainwater has been harvested and used for domestic water supply in area lacking good alternative water sources, especially in loess plateau of the northwest China.

There the rainwater harvesting system in general;, consists of ground catchment area, collecting drain, silt trap, sedimentation tank, screen and water cellar.

The initial cost for 20 m3 storage volume was equivalent to U.S. Dollar 35 that could be afforded by a farm family in general. In China, rainwater cistern systems have been mainly used for domestic water supply in rural areas where groundwater is unfit for human consumption, such as bitter brine water in Northwest plateau or surface water is heavy polluted with wastewater discharged from the village enterprises in Southeast coast. The cost of purification for facilities, maintenance and operation would be extremely high due to the advanced treatment: processes have to be applied for those water sources. Rainwater has been, therefore, harvested and used popularly for domestic water supply in areas lacking good alternative water sources especially in loess plateau of the Northwest, where annual rainfall is pretty low, only 316mm,and its 64% is concentrated, between July and September each year. There the groundwater either containing a great number of minerals, is too bitter to drink, or too deep to withdraw, otherwise, surface water is very seldom and too far to transport, more than 10 km from the water source to the consumers. The deep wells with the high lift pump have been, on trial built in some areas, but it ceased because too high cost to operate in comparison with very low output for drinking water supply. Seeing that, more than 0.2 million cement

Paper 10.5

Rain Water Harvesting Systems In Southern Africa

John M Erskine
University of Natal, South Africa

Abstract

Poor water supplies and sanitation services continue to be critical problems in the less developed rural areas of southern Africa despite considerable effort to improve and expand access. It is widely recognized that safe, easily available water supplies provided in a form acceptable to the communities concerned are essential for rural development.

Most rural communities depend on local sources of water which are available naturally - river water, open wells and springs - and these are frequently polluted. Not nearly enough use is made of rain water collection systems.

This paper describes the research and development work conducted on rain water harvesting systems in southern Africa in recent years. A case study is referred to for the purpose of illustrating the approach being used to meet the water needs of communities in some less developed rural areas for domestic as well as agricultural use, with particular reference to the introduction of simple, cost effective rain water harvesting technologies. The approach emphasizes the need for attention to be given to community involvement, through appropriate institutional arrangements, in choosing suitable technologies.

Paper 10.6

The Necessity And Scope Of Rainwater Harvest In Bangladesh.

Md. Rafiqul Hoque
Bangladesh Agricultural University, Bangladesh

Abstract

Bangladesh is a tropical country influenced by Monsoon climate. The average annual rainfall is about 2300 mm. But more than 80% of that rainfall occurs during a short period (May-August) resulting in huge runoff volume and subsequent floods. On the other hand, during the dry season (Nov. - Feb.), there is almost no or very little-rainfall resulting in too much shortage of water with subsequent severe draught conditions. Due to this two extreme and opposite conditions prevailing in Bangladesh the total economy of the country is suffered tremendously

In this paper, with respect to taking care of this two extreme situations to some possible extend, the necessity and scope of rain water harvest in Bangladesh has been discussed and suggested some strategies.

Paper 10.7

Malian Experience In Rain Water Cistern Systems

Souleymane Kone
Groupe de Recherches et d'Applications Techniques (GRAT), BAMAKO/MALI

Abstract

Water needs, supplies and uses constitute a compound subject in Mali. The appropriateness between water needs and resources Varies throughout the year. The rain season (2 - 4 months long) undergoes serious climatic disturbances these last two decades. People do not have enough access to water, because there is not enough systems (wells, reservoirs, pumps) to make the most of the potential water supply and the situation becomes more complex with the nature of the persons who support all the water supply charge. Whatever the reason, water shortage is especially prevalent in rural areas.

In this complex water supply system, the surety technology is not necessarily the one which occurs more water at less cost, but which occurs water at a specific moment in a specific place. It is the case of rain water cistern and catchment systems, which exempt women from supply duties at the moment when they have heavy agricultural charges.

The rain water cistern and catchment systems used in Mali depend on the geoclimatic factors of the different regions, the nature of the needs to satisfy (domestic, agricultural) and the way of life of the people (settlement).

According to the nature of the need, there are individual and collective implemented systems. Some of the systems are widely used in many areas and the others are known only in a small part. The importance of the rain water cistern and catchment systems is well known in Mali.

Traditional and modern techniques have been presented and the constraints and limits analysed for more wide application and efficiency use.

Paper 10.8

Rain Water Cisterns - A New Approach To Supplement The Rural Water Supply System In Sri Lanka

Rajindra De Silva Ariyabandu
Agrarian Research. and Training Institute, Sri Lanka:

Abstract

The envisaged target for the IDWSS decade in Sri Lanka was to construct 16,000 tube wells to provide adequate safe drinking water for the rural population. However, due to the unsettled situation in the country coupled with lack of funding have resulted in a shortfall of 4000 tube wells by the end of the decade. It is.hoped that the target could be achieved by 1995 if funding is granted by the Government of Sri Lanka and International donors to cover the spiralling cost.of constructing tube wells.

This paper proposes a novel approach to supplement the shortfall in the tube well programme by introducing rainwater catchment through roof run-off. Having an annual rainfall of more than 1000mm in the dry zone, Sri Lanka's potential for success in this approach seems positive. This approach, if proves to be a success would. save time of the peasants otherwise used in fetching drinking Water. from distant places. The time thus saved could be utilized , in .more productive occupations like paddy coutivation or animal husbandry. Collection of rain water.will be either in jars (2-3m3) or in small tanks. which ever the cheapest and preferable in the area. Approximately, it is estimated that cost of a jar of 2m3 is 3% of the cost of constructing a tube wall. At the existing cost estimates even if the. state gives a jar free of cost to every beneficiary household in a tube well community, the state can save upto 30%.of cost of constructing: a tube well. With a drinking-water requirement of 5 liters per day per person a jar can supply drinking: water for 60 days for a family of five. With an additional jar a family can store sufficient drinking water for almost half the year. " The implementation of the project will seriously take note of the social aspects of drinking water specially from roof run-off. Project anticipates. to conduct classes to women in the community. to educate them and eliminate any myth about' drinking water off roof catchments and having, safe drinking water. The men will be. trained in, for

Paper 10.9

Rain Water Conservation In Zambia

Henry Chirwa
Department of Agriculture, Zambia.

Abstract

The Aim of the paper is to assess the need of rain water conservation for Agricultural purposes in Zambia. The paper also looks at the means and ways of rain water harvesting in the Country.

Rain water in Zambia is wholly restricted to the rainy season which is between the months of October and April.

The Eastern and Southern Parts of the Country are most of the year dry with very few perrenial rivers. This has affected Agricultural Development. Hence the other objective. of the paper is to examine the drought relief programme introduced in these areas. The paper also looks at whether or not Dam construction which forms a major portion of the programme has been effective. The paper analysis other ways of rain water conservation if they could be good alternatives to the dam construction.

Paper 10.10

Utilization Of Rain Water In Tanzania

Datius G. Rutashobya
Ministry of Water, Energy and Minerals, Tanzania

Abstract

Rain water has been in use in Tanzania for ages, but not as a significant source of rural or urban water supply. Being a poor developing country, it is faced with ,a number of problems which renders services like water supply difficult to achieve satisfactorily.

This paper looks at roof top rain water harvesting as a relatively cheap and appropriate technology that can either solve water scarcity problems or at least reduce them in Tanzania. It traces the historical background of rain water harvesting in Tanzania and points out why the method has or hasn't been adapted in different parts of the country. It looks at the present situation in Tanzania as pertaining to the availability of water for various uses, both in the rural and urban areas. It further highlights on the research efforts being currently undertaken in the country in the area of rain water catchment. The paper attempts to justify the need of popularising the utilization of rain water in Tanzania, in order to supplement the conventional waiter supply endeavours by the government.

Finally, the paper points out the problems that have rendered the technology unpopular in some parts of the country and why it is not widespread as a major water source.'

Paper 10.11

Rainwater Cistern Its Uses In Nepal - Problems, Prospects And Promotion

Ajaya Dixit
Water Nepal

Shivajee Upadhyaya
Peace Corps Nepal

Abstract

Experience of construction of few rain water cisterns in Nepal shows that the approach could be a viable water supply system in the country. The system has more relevance in settlements in ridges, spurs, river terraces and generally water critical pockets at different climatic zones. Of the several factors, cost of the storage tank appears to be the major constraint in the way of wider uses of the system. In order to make it attractive, storage system need to be built at lesser cost, when the system would be more affordable. Prototype of a tan}, that used plastic lining has been developed and is being installed in field situations, whose performances need to be evaluated. For wider promotion of the system, an action oriented approach is being pursued. The feed backs would be useful in further promotion of the rain water cistern system in the country.

Paper 10.12

Hafirs In Sudan

Ahmed Ayoub El Gaddal
Ministry of Health, Sudan

Abstract

The HAFIR is an underground :reservoir designed for storing rain water carried by streams and used for domestic water supply and for agricultural purposes in rural areas in the Sudan.

Hafirs are usually constructed where there is enough rainfall and where there is no underground water.

It is usually big enough to cater for the needs of the villagers and their live-stock for a whole season.

The Hafir is surrounded by earthen embankments and protected by barbed wire fencing from animals.

The shape of the Hafir is like a trunkated frustum of a pyramid. The average capacity of a Hafir varies from 15,000 to 250,000 m3.

There are different types of Hafirs e.g.:

  1. Conventional HAFIRS 
  2. Lined HAFIRS 
  3. Overground storage HAFIRS

Maintenance of HAFIRS depends on:

  1. Removal of slit 
  2. Cleaning of water pipes 
  3. Cleaning of canals-stilling bowels, inlets and outlets.  
  4. Compaction of eroded embankment.

Paper 10.13

Rain Water Harvesting In Sarawak And Brunei: Progress Of Its Implementation As Part Of The Rural Water Supply Development

K.C. Goh
University of Brunei

Abstract

Piped water supply to homes definitely has a better coverage in Brunei Darussalam than in neighbouring Sarawak. Nevertheless in some isolated villages where no reticulated system exists and where shortages from natural streams during dry spells occur, rain water harvesting has been introduced. In Sarawak the problem of developing rural water supply is much more difficult as the population is widely scattered in the coastal swampy plains and the interior. In the coastal plains concerted efforts have been made by the government to introduce rain water cistern systems as a viable means of potable water supply to the more than 500 village settlements of varying sizes. This paper examines the rain water harvesting plan in Brunei Darussalam and in particular Sarawak, and the extent of success of its implementation to date.

Paper 10.14

Rainwater Cistern System In Malaysia Reconsidered

Uzir bin Abdul Malik
University Kebangsaan Malaysia

Hamidon bin Othman
Ministry of Health Malaysia

Introduction

It has been almost a decade since an attempt was made to examine the policy and practice of rainwater cistern system (RWCS) in Malaysia. The main aim of this paper is therefore to review the development of RWCS over the past decade and consider its future prospect. This is especially in view of the massive rural water supply programme undertaken by the government particularly during the second half of the decade.

It has to be mentioned at the outset that RWCS in Malaysia is essentially a rural water supply system. There has been no attempt on the part of any agency related to water supply to introduce the system in an urban environment and: attempts by private individuals to utilize this source of supply can be said to be minimal. The urban areas has been entirely dependent on the potable system provided by the various waiver supply agencies and the folly of this over-dependence has been clearly demonstrated by the recent failure of the Malacca water supply system.

Other than private efforts which are largely uncoordinated, the only programme on RWCS in the rural area is under the purview of the Ministry of Health. However, to quite an extent it could also be said that the RWCS programme of the Ministry of Health at the State levels is largely uncoordinated, This is illustrated by the absence of any clear-;:guideline on programme implementation at the policy as well as technical level.

Paper 10.15

Rainwater Harvesting As Supplemental Source For The Traditional And Modern Water Supplies For Forming Families In Malawi.

Alfred B. Osunsanya,
Meteorological Department, Malawi

Abstract

Rainwater harvesting simply means collecting rain water in some suitable reservoirs.

To achieve this simple phenomenon a systematic process has to be followed. This involves provision of an ideal surface area, referred: to as catchment-area ` and the receiving tank or reservoir referred to as cistern.

The family rainwater harvesting system is expected to provide water for all their needs, drinking, cooking -washing, irrigation etc. But there are several limiting factors that regulate the volume of water collected. The natural factors are the potential- annual rainfall and the duration of the dry season. The adjustable factors are the collection surface (roof) area or catchment area and the cistern capacity. The most important limiting factor is the FUND.

Paper 10.16

The Nakuru C.P.K. Rainwater Harvesting Project

John Mbugua
International Rainwater Catchment Systems Association - National Representative for Kenya

Abstract

The above programme started in 1984 with a goal of introducing sustainable affordable, replicable and acceptable water supply projects within 6'1/2 administrative districts which are Nakuru, Nyandarua, Narok, Baringo, Samburu, Kericho and part of Laikipia. During this period of 6 years a number of target groups have been identified and mobilized. To date the programme has over 150 active groups made up of 90% women who are also responsible for their group management. Total number of tanks constructed are over 3,0.00 and sizes:: vary from 500 gallons capacity to 30,000 gallons. This. means over 3`0,000 people and hundreds of cattle have safe water supplies at their homes'. Challenges have been in areas of research, documentation, quality monitoring and promotion of rainwater catchment system in other areas other than domestic, such as agriculture. The programme with assistance from UNICEF hosted first IRCSA workshop which attracted over 55 participants from over 20 organization including 4 ministries. There were also participants from Botswana and Tanzania.

Section 11: Technical Short Papers

Paper 11.1

Effect of Vegetation Cover on Rain Water Harvesting

AE Alizadeh, A.
Ferdowsi university of mashhad, Iran

Abstract

Vegetation influences the run oft cycle through different processes, such as evapotranspiration, interception, and reducing flow velocity._ In an investigation, the effect of vegetation management on water yield of three small watershed was studied. Management included burning and hand removal of all vegetation cover. Rainfall and collected run off were measured for each of the precipitation. The result show that both type of management increase harvested water compare to control watershed. However the effect of burning was more significant.

Paper 11.2

Rain -Water Harvesting - The Constraints

H.C. De Silva
Irrigation Department, Sri Lanka

Abstract

Water resource exploitation for human; needs has grown: by, leaps and bounds in the last two decades. Nearly all the suitable sites for storage dams and river diversions have been utilized and ground water 'extracted regardless of consequences as in Bangkok

Water for all by the year 2000 still remains an ideal, Rivers that were once perennial now become, raging torrents that convey their runoffs in the form of flash flooding.. As forests are reduced by deforestation and catchments urbanised the need to harvest rain before it reaches the dry streams beds or fall into polluted rivers becomes of paramount importance.

Runoff areas: in catchments continue to diminish and are replaced by concrete paving or bitumen. covered roads or asbestos or tiled roofs. Rainfall runoff from such artificial catchments can be collected in cisterns. above ground or in tanks below Preserving the rain close to where it fell avoids contamination that occurs with surface runoff : Percolation and. evaporation loss °is reduced: But rainfall in urban areas has its drawbacks when atmospheric pollution sulphur dioxide and carbon dioxide from vehicular traffic; coal fired power stations or industrial flue gases can convert the composition of rain to acid rain is very real.

Collection of rain in cisterns also could attract growth 'of organisms and larvae that could promote diseases like malaria, filaria, dengue and Japanese encephalitis, if such water is consumed without boiling. Water -stored in. underground- cistern could be contaminated by leakage from septic tanks. in the proximity adding nitrates and phosphorous Cisterns take up space in high value urban areas.

Population growth the world over has mushroomed to such extents that efforts made by countries to supply their basic requirements of water for drinking;. for 'irrigation and for power production can hardly copy with.

Paper 11.3

Rainwater Harvesting is Semi-arid , and Arid Eastern. Africa

Erik Nissen-Petersen
ASAL Consultants Ltd. Kenya.

In semi-arid and arid Africa there are several methods of harvesting rainwater as water supply for people, livestock, crops and :forestry. The method depends mainly on the features of the landscape and on the amount of labour and founds available.

Paper 11.4

Water Harvesting Practises in North-east Iran (an overview)

A. Koocheki
Ferdowsi University, Iran

Introduction

Water harvesting is a process of collecting and storing water from an area that has been treated or covered to increase precipitation runoff. The collected water is stored in a suitable container for domestic use or it is used for agricultural purposes. The latter in normally :referred to as runoff farming and is used to provide water for the growing crops

Much of the early history of rainwater harvesting has its origin in Europe. The Romans achieved considerable control of runoff by building structures to modify the outflow of lakes. Runoff vas collected for the primary purpose of running watermills, forming fish ponds or for recreational purposes. Rain water harvesting techniques for agriculture were extensively practised throughout a vast region of North America, South America, North Africa, Middle East, China and India. This technique was flourished in Negev desert during the days of Roman Empire, when the Roman trade mute to the East passed through the area

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