Showing papers on "Rainwater harvesting published in 1993"

Preliminary Observations on Water Quality of Storm Runoff From Four Selected Residential Roofs

Abstract: Storm runoff from four characteristic types of residential roofs and incident rainwater were monitored for 47 storm events over a six-month period at Nacogdoches, Texas, to study water quality conditions for 20 element and four chemical variables. The total element concentration in storm runoff from each roof type was greater than that of rainwater in the open. Differences in element concentrations in storm runoff among the four roof types were statistically significant (α≤ 0.05) with the differences for the wood shingle roof being the greatest and that for terra cotta clay roof being the least. The median concentrations of four element variables exceeded the Texas surface water quality standards, while 12 variables exceeded the standards at least one time in all samples collected. Zinc concentrations violated the Standard ranging from 85.7 percent of the samples for the wood shingle roof to 66.0 percent for the composite shingle, the greatest exceedances of all 24 variables studied. Storm characteristics and gutter maintenance level had some effects on these water quality conditions. The study suggested that roof types can be important to water pollution management programs. More detailed studies on roof water quality in major municipalities are required.

Significance evaluation of factors controlling river water composition

Abstract: In the present paper the factors controlling river water chemistry are described and their significance is evaluated, including: climate, petrography, soils/sediments, geomorphology of the catchment area, hydrography, pollution, biological activity of rivers, and rainwater composition. The results of this study indicate that the dominant factors influencing riverwater chemistry are the climate and the petrography of the catchment area. In the case of heavily polluted rivers, pollution appears to be the dominant factor. The approach followed is based on the watershed information, e.g., climatic, geomorphological, petrographical (percentage distribution of geochemical important petrographic units), soil/sediment composition, rainwater composition, as well as the hydrographic and the hydrochemical data of the rivers. In order to achieve a better understanding of the nature of the factors influencing river water composition as well as to specify them quantitatively, multivariate statistical analyses (factor and cluster analyses) were performed on the rain-corrected hydrochemical and petrographic information of the watersheds.

Hydrogeochemistry of the shallow dutch groundwater: Interpretation of the National Groundwater Quality Monitoring Network

Abstract: Since 1979 the Dutch National Institute of Public Health and Environmental Protection (RIVM) has been developing the Dutch Groundwater Quality Monitoring Network (LMG). This network presently consists of about 350 monitoring sites. At each site, well screens are placed at two depths: 10 and 25 m below surface level. Samples are collected every year and are analyzed for all macrochemical parameters and some trace elements. Tritium contents were measured in the first sampling round. The geochemistry of Dutch groundwater is complex, due to the different sources (seawater, surface water and rainwater), complicated hydrogeology, and human impact on flow systems and pollution. Structuring or data analysis is required for the interpretation of the large number of hydrogeochemical data from such a monitoring network. An exploratory approach is to look within the data set for homogeneous groups, each with a typical (macro)chemistry. The selection criteria for the location of the monitoring sites of the LMG are mainly based on soil type and land use, and to some extent on the hydrogeological situation. However, a classification based on the two most reliable criteria, soil type and land use, does not result in chemically distinguishable homogeneous groups or water types. Fuzzy c means clustering was successfully used to discern structure and natural groups in the LMG data for 1 year. A seven-cluster model was adopted. The number of clusters was decided heuristically with the aid of nonlinear mapping, on the basis of the geographic distribution, the hydrogeochemical interpretability, and the unimodality of the distribution of the parameters per cluster. The consistency of the model is illustrated by the reproducibility of the clusters in different years. The clusters are related to geochemical processes, natural sources, and anthropogenic input and are designated as follows: (1) “seawater” in coastal areas, (2) “desalinization” in organic-rich Holocene marine and peat deposits, (3) “surface water” for downward seeping river water or surface water near the main rivers, (4) “carbonate/reduction” in peat areas or old groundwater in seepage zones, (5) “carbonate” for carbonate-dissolving “precipitation,” (6) acid “precipitation” water in sandy topographic highs, and (7) a “polluted” cluster characterized by agricultural contaminants. Although the influence of soil type and land use is noticeable in some of the clusters, the geochemical controls, which characterize the different clusters, appear to outweigh their anticipated influence on the hydrogeochemistry on the scale of the national groundwater network. Consequently, the homogeneous groups, obtained through the cluster analysis, present a better base for further statistical and hydrogeochemical evaluation than, e.g., a stratification of the data based on soil type and land use.

Effect of oil pollution on fresh groundwater in Kuwait

Abstract: Massive oil fires in Kuwait were the aftermath of the Gulf War. This resulted in the pollution of air, water, and soil, the magnitude of which is unparalleled in the history of mankind. Oil fires damaged several oil well heads, resulting in the flow of oil, forming large oil lakes. Products of combustion from oil well fires deposited over large areas. Infiltrating rainwater, leaching out contaminants from oil lakes and products of combustion at ground surface, can reach the water table and contaminate the groundwater. Field investigations, supported by laboratory studies and mathematical models, show that infiltration of oil from oil lakes will be limited to a depth of about 2 m from ground surface. Preliminary mathematical models showed that contaminated rainwater can infiltrate and reach the water table within a period of three to four days, particularly at the Raudhatain and Umm Al-Aish regions. These are the only regions in Kuwait where fresh groundwater exists. After reaching the water table, the lateral movement of contaminants is expected to be very slow under prevailing hydraulic gradients. Groundwater monitoring at the above regions during 1992 showed minor levels of vanadium, nickel, and total hydrocarbons at certain wells. Since average annual rainfall in the region is only 120 mm/yr, groundwater contamination due to the infiltration of contaminated rainwater is expected to be a long-term one.

Curbing rural exodus from tropical drylands

Abstract: A crucial means of curbing the outflow of carbonaceous materials, nutrients and pollutants to coastal waters is to minimize the rural exodus into coastal cities. This is an issue of increasing ecological security in the dry-climate tropics and subtropics, now hosting most of the poor countries. A diagnostic diagram is presented to clarify fundamental differences in terms of environmental preconditions for human activity, in particular, the drought-proofing of crop yields. Attention is drawn to the possibility of transforming presently huge nonproductive evaporation losses into productive evapotranspiration. It is stated that the potential biomass production in drylands is preconditioned by the water availability, which in turn determines the potential of these regions to function as macro-scale carbon sources and sinks. Introduction of new agricultural techniques, in order to respond to increased biomass needs of growing populations, influence the actual capacity of carbon storage in agricultural lands. The article discusses the linkages between biomass productivity, capacity of carbon storage and choice of agricultural techniques. Rainwater partitioning over a catchment is discussed as partitioning between two complementary types of water-dependent production. On the one hand, biomass production in agriculture and forestry returns huge amounts of water to the atmosphere, while on the other hand economic production has to be based on the remaining water surplus recharging local aquifers and rivers. 64 refs, 5 figs

Water Conservation in Oman

Abstract: Limited resources and growing needs for water have triggered a nationwide campaign for water conservation in the Sultanate of Oman. A land and soil survey study of Oman shows the availability of more arable land than present water resources could support. Groundwater is the main source for agricultural production. Overpumping at rates higher than the natural recharge has resulted in lowering of the ground water table, while seawater intrusion has led to an increase in soil salinity. A comprehensive water program is underway to: (1) conserve water through efficent irrigation, use of soil additives, modern irrigation systems, agronomic management, and institutionalization; and (2) augmentation of resources via introduction of more desalinization plants, more waste water treatment, use of brackish water; water fog collection, and water harvesting by building recharge dams.

Rain-drinking behaviors of the Australian thorny devil (Sauria: Agamidae)

Abstract: During natural and simulated rainfall, Moloch horridus used the cutaneous surface of its integument as a water-harvesting system to capture rain water for drinking. Circumstantial behavioral evidence, in combination with experimental studies (Withers, 1993), suggests that the capillary, interscalar, water-transport system of Moloch is also used to absorb water for drinking from rain-moistened substrates. Lizards rub their venters against wet substrates and dig sand onto their backs. This is a previously unreported behavior for water acquisition by lizards inhabiting arid regions. No stereotypic behavioral stance for rain harvesting, as seen in Phrynocephalus helioscopus and Phrynosoma cornutum, was observed in Moloch horridus

Enhancement of chlorophyll a production in Gulf Stream surface seawater by synthetic versus natural rain

Abstract: Rainwater concentrations of either ammonium or nitrate were sufficient to stimulate chlorophyll a (chl a) production in bioassay experiments using Gulf Stream surface water collected off North Carolina during the summer of 1991. Previous studies primarily examined inshore waters and did not address the impact of rainwater ammonium. An increase in chl a occurred within 1 d of the addition of synthetic rainwater (2 or 5% rainwater, 98 or 95% seawater) containing up to 10 μM ammonium; this increase was followed by a decrease in chl a the following day. A similar response to nitrate addition (5% addition of 20 μM nitrate rain) was observed. In separate experiments, natural rainwater having nitrate and ammonium concentrations less than those in the experimental synthetic rain yielded a greater chl a response than synthetic rain when added at similar dilutions (0.5 to 5.0% rain). The maximum dissolved inorganic nitrogen concentration in the enriched seawater in these bioassays was 1.8 μM; prior to enrichment the maximum was < 0.4 μM. Bioassay experiments begun 2 d after a major storm event (sustained NE winds with gusts to 13 m s-1 and ca. 390 μmol m-2 inorganic nitrogen deposition from rain) showed a chl a increase in response to addition of natural rainwater, but not to synthetic rainwater with similar dissolved inorganic nitrogen concentration. These results suggest that phytoplankton stimulants, in addition to nitrate and ammonium, exist in natural rain but not in the synthetic rain used in these experiments.

Multivariate statistical analysis of precipitation chemistry in northwestern Spain

Abstract: 149 samples of rainwater were collected in the proximity of a power station in northwestern Spain at three rainwater monitoring stations. We analyze the resulting data using multivariate statistical techniques. Firstly, the Principal Component Analysis shows that there are three main sources of pollution in the area (a marine source, a rural source and an acid source). The impact from pollution from these sources on the immediate environment of the stations is studied using Factorial Discriminant Analysis.

Water storage/recycling unit

Abstract: A water storage/recycling unit comprises a water storage tank (11), pipework for directing waste water (10) and/or rainwater (9) from an adjacent building into said tank, and a pump unit (1) which draws water from said tank (11) and distributes it via tap (13).

Identification of overdeveloped zones of ground water and the location of rainwater harvesting structures using an integrated remote sensing based approach—a case study in part of the Anantapur district, Andhra Pradesh, India

Abstract: The Kuderu macro watershed lies in the middle reaches of Pennar river basin in Anantapur district, Andhra Pradesh, India. There is great need and demand for ground water for irrigation and drinking purposes, due lo frequent failure of monsoons and recurring drought. The majority of the irrigated wells are dried up and the ground water is extracted from the deeper aquifers, to meet the acute shortage of water. In this article, an attempt has been made lo make a quantitative estimate of ground water resource at the micro level using conventional techniques, hydrogeomorphological and hydrogeological mapping using remotely-sensed data. Multi-spectral and multi-date satellite data from IRS LISS-1 and Landsat-TM were utilised to assess the hydrogeological characteristics as well as ground water irrigated areas. The rainwater harvesting structures are recommended in the ground water overdeveloped villages to recharge the irrigated wells for further utilisation and management.

Rain water treating and conveying installation for use as industrial water or for treatment for the purpose of infiltration or inflow in receiving water

Abstract: 1. Designation Installation for treating, storing and conveying rainwater for use as utility water or for treatment for percolation or passing into an outfall. 2. Summary 2.1 Objective The aim of the invention is low-maintenance and inexpensive treatment, purification and storage of rainwater for use as utility water in homes, industry, commerce and public buildings or for the purpose of percolation or passing into an outfall, taking into account frost-proofing, with low expenditure on maintenance, without parts which wear, with a regenerable filter, with a frost-dependent filling level, with a damming-secured overflow and compact construction. 2.2 Solution of the technical object The rainwater is purified by rapid sedimentation, filtration through a depth filter and subsequent slow sedimentation. The filter is furnished with a washable, removable filter packing and, by the special construction form, makes possible high filter cross-sectional areas with low structural volume. Variable overdamming makes possible frost-proof laying of the drains in accordance with standards, without loss of filling level in the storage. Devices for forming layers and flow guidance in the storage free the water from suspended matter before withdrawal by slow sedimentation. Variable maximum water level, depending on the external temperature, make the use of an enlarged storage volume possible in frost-free seasons. 2.3 Area of application The main use of the described installation is the treatment of roof run-off water for utility water purposes. The treatment of surface run-off water from sealed surfaces is equally possible. In addition, the rain run-off from sealed surfaces can be purified by this system prior to percolation or passing into an outfall.

System for collecting rainwater for use in window-washer systems of vehicles

Abstract: The invention relates to a novel design of a system for collecting rainwater on motor vehicles and is characterised by at least one shovel-like water-collecting piece, which can be secured in a water channel, water run-off or similar rainwater-guiding region of a vehicle body, and is also characterised by a conduit connecting the collecting piece to a water reservoir of a window-washer system.

Regional water scarcity -- a widely neglected challenge.

Abstract: Most of the worlds population growth is taking place in developing countries. Thus it is important to address the problem of meeting the subsequent growing demand for food. Fresh water and food are required for sustaining human life. To produce food requires considerable amounts of water. Water-scarce countries have 5 obstacles: period wet and dry seasons most of the year is dry recurrent droughts erodible or impenetrable soils resulting in desiccation and low recharge of aquifers and rivers. These conditions hinder their ability to become self-reliant in food production. Developing countries need to adopt an approach to water supply problems of finding how much water moves in and out of the ground and of the atmosphere and then determine how to best benefit from it specifically an integrated approach to land and water. Decision makers must consider that forestry and land use practices affect the runoff of water. For example tree growth and crop production consume rainwater including returning water to the atmosphere via photosynthesis leaving less water to recharge aquifers and rivers. Water takes on soluble pollutants as it moves through the environment and the atmosphere. Water storage is needed in arid areas but construction of dams and reservoirs stirs conflict between human rights of local people adversely affected by construction and those of the people in drought-prone areas who would benefit from this construction. Population growth in urban areas requires bringing more water from ever more distant sources reducing the amount needed for irrigation. For example Coimbatore district in India is diverting irrigation water from the Bhavani River system to support industrial growth Further the untreated waste of growing urban populations jeopardizes the groundwater and rivers. Inadequate rural development is fueling the population explosion in urban areas. Countries need to take actions to improve rural living conditions such as job creation and land rehabilitation.

Rainwater-collecting installation with a cistern

Abstract: Rainwater-collecting installation with a cistern, having a container (3) which is provided upstream of the cistern (2), a device for dividing up the incoming rainwater being provided in said container (3).

Effects of seedbed preparation, irrigation and water harvesting on seedling emergence at the Nevada Test Site

Abstract: Approximately 800 hectares on the US Department of Energy Nevada Test Site and vicinity are contaminated with plutonium. As part of a cleanup effort, both the indigenous vegetation and the top 5--10 cm of soil may be removed, and the soil may or may not be replaced. Technologies must be developed to stabilize and revegetate these lands. A study was developed to determine adaptable plant species, methods to prepare seedbeds for direct seeding and water harvesting, and proper irrigation rates. Plots were cleared of indigenous vegetation, and then prepared with various seedbed/water harvesting treatments including, pitting, land imprinting, and mulching. Other plots were treated with large water harvesting structures. Three irrigation treatments were superimposed over the seedbed/water harvesting treatments. Seedling emergence data was collected, and the treatment combinations compared. Supporting meteorological and soil data were collected with an automatic data-logger. Specific data included precipitation, and air temperature. In a year of above-average precipitation, irrigation did not generally aid germination and emergence of seeded species, and only slightly increased densities of species from the native seedbank. With the exception of increased shrub seedling densities in desert strips, there were no strong seedbed preparation/water harvesting treatment effects. In years of above-average rainfall, more » mulching and water harvesting treatments, irrigation may not be necessary to insure adequate germination and emergence of adapted perennial grasses, forbs, and shrubs in the Mojave/Great Basin Transition Desert. Future collection of survival data will determine whether a maintenance irrigation program is necessary to ensure establishmnent of native plants. « less

Rainwater storage and cleaning unit - installed in ground for surge storage and natural purificn. of water

Abstract: A water storage and cleaning unit, installed in the ground for temp. storage of rainwater fed by a collection line (3), from artificial and natural collection surfaces (1), has a vegetation-covered collection tank with a drain (43) at the lowermost point for discharging settled sludge and suspended matter. The novelty is that the collection tank (13) is surrounded by a shallow water zone (19) and an overgrown bog zone (15), the shallow water zone (19) being sepd. by a wall (23) from the deep water (25) of the collection tank (13) and, together with the collection tank (13) and the bag zone (15), being sealed against the subsoil. ADVANTAGE - The unit can retain short term large water quantities, provides (pre-) cleaning of the water by natural agents (e.g. vegetation and gravel) and provides later controlled delivery to a clarification plant or drainage into the soil. It can be used as a swimming pool with natural water purificn. and can provide service water, e.g. for toilet flushing, washing or watering plants.

Rain and run-off water pre-cleaning appts. - removes dirt and allows withdrawal of relatively clean water

Abstract: Appts. for precleaning pptn. and/or run-off water, by sepn. of dirt and dirty water to recover partially clean water, has a sepn. chamber (2) with a water inlet (5), a sludge trap (4) and an overlying dirty water overflow (6) connected to a dirty water drain (7). A partially clean water outlet (9) is located above the sludge trap (4) and the inlet (5), but below the dirty water overflow (6), and a small vol. drain (8) is connected to the dirty water drain (7) and is located above the sludge trap (4) but below the partially clean water outlet (9). USE/ADVANTAGE - For treating rainwater and run-off water, e.g. from car washes to recover partially clean water e.g. for use in cleaning or for introduction into the eco-system. It delivers only sediment-free water at the partially clean water outlet, prevents the initial incoming water from entering the partially clean water, provides continuous dirt discharge by means of the small vol. drain, allows water to reach the partially clean water outlet only when the water level has rise sufficiently (e.g. during heavy and long rain periods) and provides constant redn. in water level during dry periods.

Rainwater collection and seepage disposal - involves barrel-like containers sunk in ground with rainwater seeping out of joints

Abstract: A tapering barrel-shaped tank (2) is let into the ground to collect rainwater from roofs or paved areas. A second or more tanks (3, 5) are placed abutting against the open ends, such that a series of overlapping joints (4) are formed. Rainwater is fed (6) into the arrangement through one or more pipes, and as the outer level rises, water seeps out through the joints to soak away into the surrounding soil (1). USE/ADVANTAGE - For disposal of rainwater in small domestic situations.

Glasshouse and gutters therefor

Abstract: A glasshouse uses one-piece aluminium gutters (4) for collecting rainwater and also condensate. The gutter (4) is provided with chambers (14) for receiving structural bars (10) and close to the top of each bar receiving chamber (14) there are flanges (23) for supporting transparent roof panels (8). The top piece of the gutter connecting the flanges (23) is made narrower than the width of a foot (24) to provide enhanced light transmission.