Showing papers on "Rainwater harvesting published in 2003"

Rainwater harvesting as an adaptation to climate change

Abstract: Extreme climate events such as aridity, drought, flood, cyclone and stormy rainfall are expected to leave an impact on human society. They are also expected to generate widespread response to adapt and mitigate the sufferings associated with these extremes. Societal and cultural responses to prolonged drought include population dislocation, cultural separation, habitation abandonment, and societal collapse. A typical response to local aridity is the human migration to safer and productive areas. However, climate and culture can interact in numerous ways. We hypothesize that people may resort to modify dwelling environments by adapting new strategies to optimize the utility of available water by harvesting rain rather than migrating to newer areas. We review recent palaeoclimatological evidence for climate change during the Holocene, and match those data with archaeological and historical records to test our 'climate change-rainwater harvest' hypothesis. We find correlation between heightened historical human efforts for construction of rainwater harvesting structures across regions in response to abrupt climate fluctuations, like aridity and drought. Historical societal adaptations to climate fluctuations may provide insights on potential responses of modern societies to future climate change that has a bearing on water resources, food production and management of natural systems.

Resilience building and water demand management for drought mitigation

Abstract: Doughts resulting in complete crop failure are common in Eastern and Southern Africa. We are at present experiencing a regional crisis, where crop failures related to drought are threatening the lives of millions of people in several countries in Southern Africa. A major challenge is to seek ways of mitigating and coping with droughts in small-holder farming systems, particularly in semi-arid regions which are most hardly hit by the effects of drought. An entry-point for drought mitigation is to build water resilience of present rainfed farming systems. The water balance is a good starting point to assess the options. As has been argued for decades, the term drought is very debated, and the boundaries between droughts being politically and biophysically defined is not sharp. Often crop failures and social suffering are blamed on drought, while in reality the causes are more complex than only a decline in rainfall. A challenge is to find management strategies to deal with the unreliable and extremely variable rainfall in savannah environments. In this paper examples of small-scale management practices to mitigate drought in semi-arid rainfed farming are presented. Focus is on water harvesting systems for supplemental irrigation. It is shown that with relatively simple and cheap means it is possible to build resilience to deal with water scarcity in semi-arid farming systems. If such measures are combined with efforts of maximising plant water availability and plant water uptake capacity, there are good chances of mitigating certain droughts. Conservation tillage systems have proven to maximise rainfall infiltration and storage of water in the soil, enabling even crops lacking supplemental irrigation to bridge severe dry spells. Interestingly, building resilience in rainfed farming systems is also a means of water demand management. More crop is produced per drop of water in resilient farming systems, which reduces the amount of water needed to produce food. Despite the opportunities to build resilience to mitigate droughts, it is impossible to escape from the severe drought years. This is where coping mechanisms are required, which involve social, economic and institutional preparedness to cope with the social effects of climatic droughts.

Potential of rainwater harvesting in urban Zambia

Abstract: This paper was associated with a WARFSA funded research project “Potential of rainwater harvesting in urban Zambia”. The general objective of the research was to investigate the applicability of rainwater harvesting in urban Zambia. This paper presents the results obtained at the time of writing the paper. Rainwater harvesting was not new to Zambia and there had been installations which were mainly confined to rural areas. Laboratory analysis of water samples from one such system showed that the water was suitable for drinking purposes. Two peri-urban areas of Lusaka were selected mainly based on the water stress in the areas. The socio-cultural survey conducted in the two areas indicated that water ranked among the top two priorities by the Residential Development Committee. Design of the systems was based on the mass curve analysis for storage and rational formula for the gutters. However, a maximum storage of 10 cubic meters was chosen due to budgetary limitation. Construction of five systems was in progress.

What is the limit of up-scaling rainwater harvesting in a river basin?

Abstract: The semi-arid savannah environment (SASE) of sub-Saharan Africa are characterized by low erratic rainfall which result to high risk of droughts, intra-seasonal dry spells and frequent food insecurity. The main occupation is subsistence small-scale rainfed agriculture and livestock production, which normally compete for the limited water resources. The main challenges to improving the livelihoods of the small-scale farmers are how to upgrade rainfed agriculture to improve rural livelihoods and conserve nature, and upgrade upstream landuse in balance with water needs for human and ecosystems downstream. There is an increased interest in opportunities of improving rainfed agriculture through adoption of rainwater harvesting (RWH) technologies. However, there is inadequate knowledge on hydrological impacts and limits of up-scaling rainwater harvesting at a river basin scale. Rainwater harvesting has a potential of addressing spatial and temporal water scarcity for domestic, crop production, livestock development, environmental management and overall water resources management is SASE. However, this potential has not been exploited despite the occurrence of persistent low agricultural production and food shortage in sub-Saharan Africa. The need to quantify this perceived potential and related hydrological impacts on a river basin led to the on-going research project titled “hydrological impacts of up-scaling RWH on upper Ewaso Ng’iro river basin water resources management”. It is envisaged that the study will contribute to formulation of sustainable RWH up-scaling strategies to enhance food production and hydro-ecological balance in semi-arid savannahs of Africa. This paper presents the preliminary findings of the study mainly focusing on assessment of the potential of RWH technologies for improving food and water availability especially in semi-arid regions of eastern Africa. This was achieved by evaluating six RWH case studies selected from four countries (Ethiopia, Kenya, Tanzania and Uganda). Despite the success of a number of RWH systems, the rate of adoption is still low, hence making their impacts marginal. Nevertheless, there is a knowledge gap on the limits of up-scaling RWH in a river basin, which the other components of the study will address. The assessment of the hydrological impact of up-scaling RWH technologies is expected to provide answers to the question, what is the limit of up-scaling rainwater harvesting in a river basin ?

Efficient management of rainwater for increased crop productivity and groundwater recharge in Asia.

Abstract: Rainwater is the main source of water for agriculture but its current use efficiency for crop production ranges between only 30 and 45%. Annually, 300–800 mm of seasonal rainfall are not used productively, as the rainfall becomes surface runoff or deep drainage. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)’s long experience, in partnership with national agricultural research systems, in integrated watershed management has clearly demonstrated that areas with good soils in the semi-arid tropics (SAT) in Asia can support double-cropping, while surplus rainwater could recharge the groundwater. In the integrated watershed approach, the emphasis is on in situ conservation of rainwater at farm level, with the excess water being taken out of the fields safely through com- munity drainage channels and stored in suitable low-cost structures. The stored water is used as surface irrigation or for recharging groundwater. Following conservation of the rainwater, its efficient use is achieved through choosing appropriate crops, improved varieties, cropping systems and nutrient and pest-management options for increasing productivity and conserving natural resources. Longterm, on-station watershed experiments have demonstrated that Vertisols with a rainfall of 800 mm have the capacity to feed 18 persons haϪ1 (4.7 t of food grains haϪ1) compared with their current productivity of 0.9 t haϪ1 supporting four persons haϪ1. This increased productivity can be achieved if the productivity of rainwater is doubled (from 30% to 67%) and the soil loss is reduced by 75% compared with the loss under traditional methods of cultivation. By adopting such a holistic approach to the management of rainwater in partnership with the communities, crop productivity in the watersheds is substantially increased (up to 250%), groundwater levels improved and soil loss minimized. Results from such on-farm integrated watersheds are discussed. Conditions for success in the improved management of rainwater are: community participation, capacity building at local level through appropriate technical guidance and the use of new scientific tools to manage the watersheds efficiently. To sustain agricultural productivity in the SAT, this holistic approach of watershed management needs to be scaled up through appropriate policy and institutional support and its on-site and off-site impacts need to be studied.

Analysis of the Performance of Rainwater Tanks in Australian Capital Cities

Abstract: The performance of IkL to 10 kL rainwater tanks with mains water tickle topup used to supplement mains water supply for domestic toilet, laundry, hot water and outdoor uses was evaluated for Brisbane, Sydney, Melbourne and Adelaide. The PURRS (Probabilistic Urban Rainwater and wastewater Reuse Simulator) model developed by Coombes and Kuczera (2001) was employed to continuously simulate the performance of rainwater tanks using synthetic pluviograph rainfall generated by the DRIP (Disaggregated Rectangular Intensity Pulse) event based rainfall model by Heneker et al. (2001). Depending on roof area and number of occupants in a household, the use of rainwater tanks resulted in annual mains water savings ranging from 18 kL to 55 kL for 1 kL rainwater tanks to 25 kL to 144 kL for 10 kL rainwaters tanks. The average retention volumes available in rainwater tanks prior to storm events ranged from 0.26 m3 to 0.71 m3 for 1 kL tanks to 2.34 m3 to 8.4 m3 for 10 kL tanks.

Rapid soil moisture recharge to depth by roots in a stand of artemisia tridentata

Abstract: The temporal patterns of soil water potential in a stand of Artemisia tridentata in central Utah, USA, were monitored during the summer, which included small periodic rainfall events, and over the winter, when most of the soil recharge occurs in this environment. The pattern of recharge, when compared to an area cleared of aboveground vegetation, strongly indicated that the downward movement of water to 1.5 m was primarily conducted via roots by the process known as hydraulic redistribution. Rainwater was moved rapidly downward shortly after the rain event and continued over a period of a few days. For rainwater reaching a 0.3–1.5 m depth, the portion redistributed by roots was estimated to range from 100% for small rainfall events (<8 mm) to 74% for a 36-mm event. Simulations with a model of soil water movement that compared situations with and without hydraulic redistribution by roots, indicated that during the fall–spring recharge period, 67% of all water moved downward below 0.1 m was via roots, while...

Field guide to appropriate technology

Abstract: Preface Introduction Culture and Transfer of Technology Design Philosophies for Appropriate Technology Being a Volunteer Overseas 1. Planning and Implementation Overview Development Project Management The New Participation Prelude to Participatory Management Social Assessment and Stakeholder Participation The Human Side of Change Gender and Technology in the Field Managing a Small Business Operations Purchasing Policy and Procedures Marketing Financial Viability and Cash Flow Statement Costing Discounted Cash Flow Microfinance Planning Project Selection Project Evaluation How to Evaluate Management of Projects Design and Construction Oversight Responsibility for Getting Job Done Emergency Response Program Disaster Relief Exit Strategy Training Thinking and Learning Together Grant Writing Fund Raising: Social Service Agency in Bolivia A Summer Internship in Guatemala 2. Energy Energy Planning Basics of Electricity Hydropower WindPower Photovoltaics Cook Stoves Solar Cookers Solar Heating (Needs Editing) Evaporative Cooler Charcoal Production Fuel Cells Batteries Alcohol as Fuel Tidal Power 3. Food Introduction Agricultural Machinery Hydroponics, Rooftop and Related Gardens Urban Gardens Sustainable Agriculture Hammer Mill of the ELC CAR Oil Press Vegetable Gardening Intensive Gardening Soil Fertility And Fertilizer Use Amaranth: Grain and Vegetable Use Cassava Production Cereal Cultivation Coconut Production Fruit Growing Under Marginal Conditions Growing Rice Rice Paddy: Harvesting, Threshing, Cleaning, and Handling Shitake Mushrooms Agroforestry Principles Aquaculture Beekeeping Raising Cattle Raising Chickens Raising Ducks Ostrich Production Raising Pigs Raising Rabbits Raising Sheep and Goats Nutrition 4. Health Overview Words to the Village Health Worker Community Health Workers Health Care Delivery System Culture, Health and the Environment Medicinal Plants Versus Pharmaceuticals for Tropical Rural Health Care Traditional Health Practitioners The Traditional Medical Practitioner In Zimbabwe Medicinal Plants Water and Health Safe Abortion and Post Abortion Care Using MVA Diarrhea Malaria: Resurgence of a Deadly Disease Palliative Care for AIDS Patients The Health Impacts of Exposure to Indoor Air Pollution Exposure to Indoor Air Pollution from Biofuel Stoves in Rural Kenya Dental Health Care Third World Health Care Needs Health Guidelines for Travelers 5. Construction Building Building Bibliography Building with Arches, Vaults, and Cupolas Cob Structures Straw Bale Construction Soil Stabilized Bricks Micro-Concrete Roofing Tile Production Thatch Gypsum Bamboo Reinforced Concrete Non-Poisonous Timber Protection Dry Stone Walling: Applications and Techniques 6. Transportation RickShaws and Bicycles Using Oxen for Farm Work and Transportation Pack Animals (Needs Figures) Low Cost Transport Device Wheel Manufacturing Technology Boats Earth Road Construction Small Scale Bridge Building Emergency River Crossing Ropeways in the Hindu Kush 7. Household Technologies Spinning and Weaving Dyeing Treadle Sewing Machine Silk Production Soap Manufacturing Candles Chalk Pottery Making Basketry Making Articles from Paper Waste Making Rope Recycling and Re-Using Rubber Understanding Small Scale Paint Production Small-Scale Papermaking 8. Water Supply Water Harvesting and Spreading For Conjunctive Use of Water Resources (Needs Fig.) Rainwater Collection Water Saving and Reuse Wells: Hand Dug and Hand Drilled Solar Stills Filtration and Disinfection Sanitation Latrines Composting Toilets Water Pumps Hydraulic Ram Irrigation 9. Tools Thinking about Tools Safety Basic Hand Tools Sharpening Tools Basic Technical Math Machine Tools Blacksmithing Folding Machine for Sheet Metal Work Wire Fence Making Machine 10. Other Technologies Important Technologies Telecommunication Services Land Mines Land Mine Detection Mining

Flux and bioavailability of Cape Fear River and rainwater dissolved organic carbon to Long Bay, southeastern United States

Abstract: [1] This study presents the first comparison of riverine and rainwater dissolved organic carbon (DOC) flux to a coastal region, and the first examination of rainwater DOC bioavailability. The bioavailability of DOC from these two sources was determined because its impact on coastal waters depends on whether DOC is labile or refractory. The study site, Long Bay, off the North Carolina and South Carolina coasts in the southeastern United States, receives external sources of DOC from the Cape Fear River system and rainwater. Conservative mixing of estuarine DOC, and a consistent DOC value for the river sources entering the Cape Fear Estuary (Cape Fear and Black rivers combined: 937 ± 178 μM, n = 12; Northeast Cape Fear River: 1266 ± 196 μM, n = 8) allowed for a calculation of DOC flux using river DOC values and U.S.G.S. river flow data. Rainwater DOC flux was determined by a deposition calculation at a rainwater collection station in Wilmington, N. C., 40 km from Long Bay. Riverine DOC flux was determined to be (77 × 109 gCyr−1) or roughly 4x the rainwater flux (21 × 109 gCyr−1) on an annual basis. The bioavailability of the riverine DOC (9.0 ± 4.5%) was much less than that of rainwater (63 ± 14%). Therefore, taking into account only bioavailable DOC, rainwater provides more labile DOC (13 × 109 gCyr−1) to Long Bay than riverwater (7 × 109 gCyr−1) meaning that rainwater is important for fueling secondary productivity whereas river DOC is important for long-term storage of carbon.

Rainwater recovery system

Abstract: A system and method for restoring the natural water cycle by reducing stormwater runoff and addressing issues affecting groundwater supply. In one embodiment of the invention, the system comprises a roof washer component, cistern component, pump, and manufactured dry well. The system is designed to divert polluted rooftop runoff, capture clean rooftop runoff and store this clean water for irrigation purposes and nonpotable uses, while infiltrating excess water to recharge groundwater supplies thereby replicating the natural hydrologic cycle.

Water Quality Treatment Processes in Domestic Rainwater Harvesting Systems

Abstract: Although the collection of rainwater for potable purposes is an ancient practice and is widespread in many parts of the world today, rainwater harvesting systems have largely been viewed as a black box. Research has neglected to investigate many important facets of rainwater harvesting including the critical area of process understanding with regard to water quality changes and treatment mechanisms. This paper overviews the possible treatment train and highlights gaps in our understanding. Exposure to UV, heat, and desiccation on the roof top destroy many bacteria. Within the tank, it is proposed that biofilms actively remove heavy metals and organics from the water, thus increasing the difficulty for planktonic organisms to survive. While many bacteria conglomerate in a micro-layer on the water surface, many of the heavy metals and other contaminants precipitate out of the water column and settle at the bottom of the tank. The precipitation of suspended solids and bacteria may also be possible during a rain event if re-suspension of the sediment occurs and acts as a coagulation-precipitation agent. Outlet taps on tanks are always located above the sediment layer, and in a trickle top up system the water surface layer is always above the outlet, effectively preventing these contaminants from being present in the available water supply. Tank water must also pass through a pump and possibly through a hotwater system, which impose sudden stresses on bacteria, disrupting cell structure and integrity. Hotwater systems maintained at 60 C in accordance with Australian Standards (AS3500.4.2) should not pose serious health risks as Legionella pneumophila, the main bacterial species of concern, are destroyed at temperatures above 50 C in water. Heat inactivation data are yet to be published for most other pathogenic species in a water medium. Rain harvesting in the urban environment produces valuable yields of water and research into treatment processes needs to be undertaken to ensure that in the future, this resource can be fully utilised.

Coping with hygiene in South Africa, a water scarce country

Abstract: The burden of infectious diseases may be reduced by adopting effective infection control measures. Some of these are dependent on the provision of adequate and safe water supplies for maintenance of basic standards of personal, domestic and healthcare hygiene. Consequences of scarce, and sometimes unsafe, waters supplies in South Africa are highlighted with reference to healthcare-associated infections, community acquired infectious intestinal diseases and domestic practices as infection sources. Availability of water in more than 67% of South African municipal hospitals and primary health care facilities (delivered by water tanker in 12.5% of satellite clinics, 5% from river or dam sources, 12.4% relying on rainwater) does not necessarily guarantee that it's quality is safe for utilisation. In the Northern Province and Mpumalanga, water needs to be purified prior to usage in 14.4 and 33% of satellite clinics respectively. Simple, low maintenance and low-cost interventions to maximise use and safety of limited water resources may be implemented: micro-organism (S. dysenteriae) inactivation by direct UV-exposure in sunlight abundant environments, water purification by filtration mechanisms and making use of iron pots in the community for pasteurisation, decontamination and boiling procedures. Education is paramount in promoting healthy domestic food handling practices, changing cultural perceptions of hygiene, hand-washing technique and mechanisms of domestic environmental decontamination. Water provision cannot be separated from other inter-related factors such as sanitation. Although the present government has taken initiatives to reduce the number of people not having access to water by 50% in 2002, provision of sanitation has been slower (>38% inadequate sanitation in 2002). Adoption of integrated environmental management approaches in conjunction with community participation (WASH Campaign--2002), by the government, aims to address the sanitation problems.

Water: A Scarce Resource in Rural Watersheds of Nepal's Middle Mountains

Abstract: Water remains one of the major issues in the Middle Mountains of the Hindu Kush–Himalayas. This most populated region of Nepal depends mainly on rainwater supply, which is highly variable: around 85% of annual rainfall is expected during the monsoon, which lasts about 4 months from June to September. During this season, the major concern in many parts of the region is flooding and surface erosion due to too much water. During the remaining 8 months, water shortage for domestic and agricultural use is a persistent problem. This article discusses water availability considerations in 2 watersheds in the Middle Mountains of Nepal. A survey of the water need and supply situation was carried out in both watersheds. The survey revealed the most needy regions within the watersheds and local residents' major concerns. Their main apprehension is water availability for both agricultural and domestic purposes, and increasingly, water quality concerns are mentioned in villages. A comparison between the 2 wate...

Economic, water quantity and quality impacts from the use of a rainwater tank in the inner city

Abstract: A dual water supply system (rainwater and mains water) has been installed at an old house in Maryville a inner city suburb of Newcastle in New South Wales, Australia. A design was developed for the installation of a rainwater tank to supply rainwater for toilet, hot water and outdoor uses. The rainwater supply is supplemented with mains water via a trickle top-up system when water levels are low in the tank. An air gap is used for back flow prevention in accordance with Australian standards. The design, construction and performance of the dual water supply system at the Maryville house are examined in this paper. Monitoring of water quality from the rainwater tank and from an instantaneous hot water service at the Maryville house has revealed that the rainwater was acceptable for hot water, toilet and outdoor uses. Rainwater used in the hot water service was compliant with Australian drinking water standards. The cost of rainwater has been found to be $0.30 per kL which is less than the price of mains water in the Lower Hunter region and the commonly assumed cost of $1.00 to $14.00 per kL.

Sustainable wastewater treatment : developing a methodology and selecting promising systems

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Hydrogeologic and climatic influences on spatial and interannual variation of recharge to a tropical karst island aquifer

Abstract: [1] The hydrology and geochemistry of groundwater in tropical island aquifers, such as on Barbados, are significantly influenced by tropical climatic conditions. Recharge to these aquifers is the product of regional and local climate patterns that control rainfall. Oxygen isotopes can be used to estimate the amount and timing of recharge on these islands because seasonal fluctuations of rainwater oxygen isotopic compositions are related to the amount of rainfall. This study shows that estimates of average annual recharge to the limestone aquifer on Barbados vary widely, displaying a more direct relationship to the distribution of rainfall throughout each year than to total annual rainfall. Recharge estimates are higher during years when rainfall is concentrated in the peak wet season months than during years when rainfall is more evenly distributed throughout the year. The El Nino-Southern Oscillation appears to be partially responsible for these rainfall and recharge fluctuations. Knowledge of interannual variation of recharge and processes responsible is important because recharge variation must be considered when setting groundwater management policies related to groundwater availability.