Source Of Potable Water Supply Research Articles

An Appraisal of Hydrogeological Conditions and Fluoride Problem in Makrana Block of Nagaur District in Rajasthan, India

Abstrct: Groundwater is one of the important sources of potable water supply in rural India. The study area of Makrana block is located in the south-eastern part of Nagaur district of Rajasthan covering about 1140 sq. km. area. The marble from the Makrana town gets the GHSR (Global Heritage Stone Resources) status recently from the IUGS. The study area experiences arid to semi-arid type of climate. Older alluvium, Quaternary Alluvium and Schist are important aquifers occur in Makrana block. Groundwater occurs under unconfined to semi-confined conditions. Groundwater quality and depth of water varies widely in Makrana block. High concentration of fluoride and nitrate are major quality problem associated with groundwater and having adverse effects on human health. High concentration of fluoride in a particular belt is so remarkable that the term BANKA PATTI (a strip of land where deformed people reside) has been in used covering parts of Parbatsar, Makrana and Degana blocks of Nagaur district wherein some villages the fluoride concentration in groundwater is over 4 ppm. The concentration of Fluoride mainly comes from Schists, Gneiss and Limestone of Proterozoic age. Higher concentration of fluoride affects metabolic activities of an individual which may cause skeletal and dental fluorosis. The disease fluorosis is non curable but preventable

GIS- and ICPR-Based Approach to Sustainable Urban Drainage Practices: Case Study of a Development Site in Florida

Stormwater control is an urgent concern in cities where the increased impervious surface has disrupted natural hydrology, particularly causing a reduction in groundwater recharge which is the source of potable water supply for many communities. Water managers are increasingly turning towards infiltration-based stormwater management options (ISMOs) to help minimize flooding and mitigate the impact of urbanization on the local hydrologic systems. This paper offers a unique hydrologic and hydraulic (H&H) modeling approach using the Geographic Information System (GIS) and Interconnected Pond and Channel Routing (ICPR) software to help quantify the associated flood stage and groundwater recharge benefits of using ISMOs. The proposed approach incorporated ICPR percolation links and utilization of the curve number and Green-Ampt infiltration methods into the case study design, as well as an analysis of the effectiveness of including low-impact development practices. This analysis shows a 13–36% reduction in stormwater volume leaving the proposed site when percolation links were utilized to account for percolation from the proposed ISMOs. These reduction provides an indirect estimate of groundwater recharge benefits. The conversion from impervious parking to a pervious one and inclusion of rainwater harvesting from the roof area resulted in a further reduction in peak stages ranging from 1.20 to 7.62 cm.

Availability, coverage, and access to the potable water supply in Oyo State Nigeria

This research centered on investigating the availability, coverage, and access to potable water supply in Oyo State, Nigeria. Relevant data was sourced from the Federal Ministry of Water Resources, Abuja, and analyses were carried out using both descriptive and paired t-test methods of analyses on SPSS. It has been established that there was availability of water supply, though inadequate, and groundwater was found to be the preponderate potable water supply source. Also, the coverage to the potable water supply was found to be 27.3% while about 62.74% have access to the available potable water supply which implies that most of the sources were from the individuals’ arrangements. To avoid overexploitation of groundwater which might have great impacts on the surroundings, it has been suggested that the government should improve on the water supply through other sources especially by improving the performance level of the existing major surface water schemes. The paired-samples t-test were statistically significant where p < 0.05 (at a 95% confidence interval), indicating a statistically strong correlation between the coverage and access to potable water with a significant increase in means from (M = 27.30, SD = 16.61, N = 33) to (M = 62.74, SD = 25.36, N = 33). Therefore, access and coverage data were divided into two parts; one part for a relationship equation development while the other part for the validation by estimating the Nash-Sutcliff Efficiency (60%) and the Coefficient of Determination (88.5%); making it possible to predict access to potable water provided that information on water supply facility coverage is known. This will improve the data gathering process and also for checking whether the Sustainable Development Goal 6.1 is met specifically in this study area.

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The article is devoted to the research of variants of drinking water supply of National Guard of Ukraine units which perform their tasks according to their assignment outside the permanent deployment points. The article also deals with theoretical provisions, which can be taken as a basis for the methodology of substantiation of the optimal plan of such supply. It is noted that drinking water is an important resource in the system of food supply of military units, the lack or shortage of which for a relatively short period of time significantly affects the combat capabilities of the units. Based on this, the possibility of diversifying the sources of drinking water supply for the needs of the troops is studied. Both traditional options of drinking water supply for NGU needs and new ones, which are expected to be implemented in practice in the near future, are considered. Expanding the list of possible sources of potable water supply will contribute to increasing the reliability of water supply and reducing the cost of related logistics operations. Taking into account the presented options for providing drinking water, possible points of delivery of bottled drinking water to units that perform their tasks autonomously in difficult conditions were identified. The presence of several points of drinking water supply to units necessitates the development of a water supply plan. One of the key requirements for such a plan is minimization of total costs. It is shown that the transport problem of linear programming can be used as the basis for developing an optimal plan for supplying drinking bottled water to military units. In this case, the target function is reduced to a minimum of total costs of water delivery. The constraints affecting the processes and determining the search area of the optimal solution are formulated, the general approach to solving the formulated optimization problem is characterized.

Increased Dissolved Organic Carbon Concentrations in Peat‐Fed UK Water Supplies Under Future Climate and Sulfate Deposition Scenarios

AbstractPeatlands are globally‐important terrestrial carbon stores as well as regional sources of potable water supply. Water draining from peatlands is rich in dissolved organic carbon (DOC), which can be problematic for water treatment. However, it is unclear how future climate and sulfate deposition changes may impact DOC in peatland‐derived potable water. The United Kingdom (UK) is a global hotspot that consumes 79% of all potable water derived directly from peatlands. Here, a physically‐based hydrological model and a biogeochemical organic carbon model were used to predict discharge and DOC concentration in nine hotspots of peatland‐derived potable water use in the UK under a range of 21st century climate and sulfate deposition scenarios. These nine catchments supply 72% of all peatland‐derived water consumed in the UK and 57% of the global total, equivalent to the total domestic consumption of over 14 million people. Our simulations indicate that annual discharges will decrease and that mean annual DOC concentrations will increase under all future scenarios (by as much as 53.4% annually for the highest emissions scenario) in all catchments. Large increases (by as much as a factor of 1.6) in DOC concentration in the 2090s over the baseline period are projected for autumn and winter, seasons when DOC concentrations are already high in the baseline datasets such that water treatment works often reach their capacity to cope. The total DOC flux is largely insensitive to future climate change because the projected increase in DOC concentration is mostly counterbalanced by the projected decrease in discharge.

Karst waters in potable water supply: a global scale overview

Karst aquifers are one of the main potable water sources worldwide. Although the exact global karst water utilisation figures cannot be provided, this study represents an attempt to make an upgraded assessment of earlier and often circulated data. The main objective of the undertaken analysis is not only to provide an assessment of the utilisation of current karst aquifers, but also to estimate possible trends under various impact factors such as population growth or climate changes. In > 140 countries, different types of karstified rocks crop out over some 19.3 × 106 km2, covering > 14% of ice-free land. The main ‘karst countries’, those with > 1 × 106 km2 of karst surface are Russia, USA, China and Canada, while among those with > 80% of the territories covered by karst are Jamaica, Cuba, Montenegro and several others. In contrast, in a quarter of the total number of countries, karstic rocks are either totally absent or have a minor extension, meaning that no karst water sources can be developed. Although the precise number of total karst water consumers cannot be defined, it was assessed in 2016 at approximately 678 million or 9.2% of the world’s population, which is twice less than what was previously estimated in some of the reports. With a total estimated withdrawal of 127 km3/year, karst aquifers are contributing to the total global groundwater withdrawal by about 13%. However, only around 4% of the estimated average global annually renewable karstic groundwater is currently utilised, of which < 1% is for drinking purposes. Although often problematic because of unstable discharge regimes and high vulnerability to pollution, karst groundwater represents the main source of potable water supply in many countries and regions. Nevertheless, engineering solutions are often required to ensure a sustainable water supply and prevent negative consequences of groundwater over-extraction.

Estimation of the Quantity of Water in the Abandoned Underground Mine of Gold Fields Ghana Limited Tarkwa: A Potential Source to Augment Water Supply to Tarkwa Municipality

The Tarkwa district is an important gold mining area in the Southwestern part of Ghana. The main source of potable water supply to the Tarkwa Nsuaem Municipality is from the Bonsa River treatment plant managed by the Ghana Water Company Limited (GWCL). The River is under threat from serious contamination by illegal mining ("galamsey") activities within its catchment area. Consequently, the amount of water supplied to the Municipality has not kept pace with its growing population due to increasing treatment cost and supply difficulties. The need to find alternative and sustainable sources of potable water supply to augment that from GWCL to the Municipality has become imperative. A large void volume created as a result of the abandoned underground mine operated by Gold Fields Ghana Limited (GFGL), after its closure in 1999 has flooded. This potential water resource is being pumped out daily, and wasted, sometimes spilling-over to low lying areas around the mine when allowed to reach its decant level. This study estimated the quantity of water in the Abontiakoon Vertical Shaft (AVS) which is part of the large underground void using survey production figures and post-closure void filling parameters resulting in 2.8 x 106 m3 and 2.9 x 106 m3 respectively. The rate of recharge to the underground water was also estimated to ascertain the sustainability of the void water should it be considered for use by employing the model of predicting rebound on “void filling” basis and average dewatering rate before closure at 2 535 m3/day and 2 618 m3/day respectively; indicating that recharge to the AVS reservoir is about 6 x 106 gal/day or 30% of current daily water supply deficit in the TNM. The estimated potential volume of mine water in storage in the entire Tarkwa underground void is 32 x106 m3. Two samples of the mine water were taken in November 2011 and February 2015 for quality analysis, in order to have a fair knowledge of the water quality parameters. The quality of the underground water was found to be potentially good, and not likely to cause any health threats, or water quality problems. Depth sampling is recommended to determine the chemical profile of the reservoir. Keywords: Reservoir, Municipality, Bonsa River, Contamination, Tarkwa

Impact of land cover on groundwater quality in the Upper Floridan Aquifer in Florida, United States

Although agricultural lands are generally assumed to correlate negatively with groundwater quality, the intricate relationship between general land cover and contaminant concentrations present in an aquifer may vary substantially; contingent upon the land type, interacting factors, and scale considered. The Upper Floridan Aquifer (UFA) is a primary source of potable water supply for the state of Florida. The Suwannee River Water Management District (SRWMD), located in northcentral Florida, relies exclusively on the UFA for water supplies. Over much of the SRWMD in the UFA is unconfined, rendering it vulnerable to contamination from surface sources. This study analyses groundwater concentrations of Nitrate-Nitrogen (NO3–N) and Potassium (K) from shallow wells across the SRWMD for assessing the effect of different land covers on groundwater quality over time. Annual potentiometric surface maps were used to delineate semicircular recharge zones of 500 m, 1000 m, and 2000 m radii upstream of sampled well stations. Proportions of agriculture, forest, and urban lands were identified for each buffer zone using USDA Cropland Data Layer. Multivariate regression models were developed to infer relationships between land cover and NO3–N and K concentrations. Results show significant associations among land cover type, water table height, and groundwater quality parameters. Specifically, we find a large proportion of agricultural cover consistently associated with larger increases in groundwater pollutant loads relative to urban or forest cover across all models, after controlling for depth to water table. Our study suggests a need for widespread adoption of cost-effective agricultural best management practices (BMPs) that could help in securing regional water supply.

Assessment of surface water quality in Legedadie and Dire catchments, Central Ethiopia, using multivariate statistical analysis

The quality of surface water in an area could be determined both by anthropogenic actions and natural processes. The current study assessed surface water quality in Legedadie and Dire catchments that cover a total area of 285 km2 in Central Ethiopia northeast of the nation’s capital Addis Ababa and within close proximity (20-30 m) from this city.. Accordingly, Addis Ababa is, and will continue to be, the major beneficiary of the the catchments which are in fact the primary sources of potable water supply to the city. Despite its potential ecosystem benefits, the catchment area was seriously affected by the rapid socioeconomic development phenomena that had been taking place in and around the city over the previous six decades. As a result, the catchment water resources are characterized by decades of deterioration because of severe pollution problems directly associated with mismanagement of natural resources coupled with other several factors. Hence, the current study was sought to examine the temporal and spatial determinants of catchment water pollutants. To that end, 14 water quality monitoring stations were selected and set up both in upstream and downstream parts of six rivers and two reservoirs. The water samples collected from different sites were monitored for 30 standard water quality parameters including nutrients, inorganic variable, and trace metals. Seasonal data were then measured for the 30 parameters monitored across two seasons (summer and autumn) over a two-year period (June 2014 – November 2015). The complex two-year seasonal data matrix that comprised of 3,660 observations was treated using multivariate statistical techniques: cluster analysis (CA), factor analysis/principal components (FA/PCA), and discriminant analysis (DA). CA successfully classified both the temporal (summer, autumn, and summer predominant) and spatial (natural, agricultural, urban, and mixed) clusters of water quality monitoring sites. Dimension reduction from FA/PCA was not as substantial as expected since it enabled only30% reduction from the original data matrix. On the other hand, DA procedures demonstrated the best result regarding data reduction and pattern recognition in both temporal and spatial analysis. It extracted data significantly and provided 5 parameters (Temp, pH, DO, salinity, and TN) to afford 96.8% right allocations during temporal analysis and only 7 parameters (pH, Turbidity, TN, Total hardness, Pb, Fe, and Cu) to yield 85.2% right allocations during the spatial analysis.Thus, these water quality parameters were most significant for seasonal and spatial water quality variation in the catchment. Therefore, DA enabled a significant reduction of the dimension of the original data matrix into a few significant parameters that affect water quality. In conclusion, the study demonstrated that multivariate statistical techniques are very useful for analysis and interpretation of complex water quality data sets for efficient assessment of water quality and identification of pollution sources as well as an effective understanding of the space and time effects of water quality.

Characterization of the Effects of Redox Condition on Fe(III)/Fe(II) Transformation in a Small Karstic Aquifer: Poocher Swamp Freshwater Lens, South Australia

&lt;p class="1Body"&gt;The presence of iron in potable water supply aquifers poses a major water quality problem and may render the supply unsuitable for domestic or industrial uses, unless appropriate treatments is undertaken. Evaluation of redox conditions in groundwater is a prerequisite for studies involving Fe(III)/Fe(II) transformation in aquifers. This study characterizes the redox conditions, geochemical evolution and distribution of iron in a small karstic freshwater aquifer, the Poocher Swamp freshwater lens, located in south-east of South Australia. The freshwater lens is formed as a result of flows from Tatiara Creek that enter Poocher Swamp and recharge the aquifer through two sinkholes located in the northwest section of the swamp. Stable isotopes of water molecules, δ&lt;sup&gt;2&lt;/sup&gt;H&lt;em&gt; &lt;/em&gt;and δ&lt;sup&gt;18&lt;/sup&gt;O, indicate that both Tatiara Creek and Poocher Swamp waters are isotopically more enriched due to evaporation than the pristine water of the aquifer. The Na&lt;sup&gt;+&lt;/sup&gt;/Cl&lt;sup&gt;-&lt;/sup&gt; ion ratio &amp;gt;0.85 for Tatiara Creek, Poocher Swamp and wells within the lens suggest additional sodium source(s) are involved in the evolution of groundwater chemistry. This study use redox potential, dissolved oxygen (DO) and dissolved organic carbon (DOC) contents to describe Fe(III)/Fe(II) transformation in the groundwater, and relate this to iron distribution within the lens. Three distinct redox zones are present in the freshwater lens; anoxic zone up to one kilometre from Poocher Swamp where dissolved oxygen (DO) is &amp;lt;1 mg.L&lt;sup&gt;-1&lt;/sup&gt;, redox potential (Eh) &amp;lt;100 mV, and iron (Fe) in groundwater 2.3-9.3 mgL&lt;sup&gt;-1&lt;/sup&gt;. Following the anoxic zone is the suboxic zone (from 1to1.5 km from Poocher Swamp), where DO is &amp;lt;1 mg.L&lt;sup&gt;-1&lt;/sup&gt;, Eh is about 110-275 mV and Fe is 0.4-0.6 mg.L&lt;sup&gt;-1&lt;/sup&gt;. The oxic zone is 1.5 to 2.3 km from Poocher Swamp and is characterized by high DO (2-4 mg.L&lt;sup&gt;-1&lt;/sup&gt;), higher Eh (&amp;gt;300 mV) and low in Fe (&amp;lt;0.015 mg.L&lt;sup&gt;-1&lt;/sup&gt;). Only 0.4 km&lt;sup&gt;2&lt;/sup&gt; of the 13 km&lt;sup&gt;2&lt;/sup&gt; area of the freshwater lens is oxygenated, thus limiting further developments of the lens as potable water supply source.&lt;/p&gt;

Potable Reuse Water and Pricing: What Does the Future Hold?

For water agencies in many parts of the United States, the need to secure reliable sources of water supplies has never been more pressing. Forecast population growth, concerns about the long‐term impact of climate change, and, of course, severe drought conditions in the southwestern and south central United States have made the acquisition and development of new water supplies a critical priority. Agencies are on the lookout for alternative water sources, and cost of water in the spot market has increased significantly. The cost of long‐term sources of potable water supply has also increased. Many water utilities are turning to nontraditional sources of supply such as large‐scale desalination and indirect or direct potable water reuse projects that were once rejected as being too expensive or controversial.

Eutrophication forecasting and management by artificial neural network: a case study at Yuqiao Reservoir in North China

Yuqiao Reservoir is the potable water supply source for a city with a population of more than 14 million. Eutrophication has threatened the reliability of drinking water supplies and, therefore, the forecasting systems for eutrophication and sound management become urgent needs. Water temperature and total phosphorus have long been considered as the major influencing factors to eutrophication. This study used the artificial neural network (ANN) model to forecast three water quality variables including water temperature, total phosphorus, and chlorophyll-a in Yuqiao Reservoir. Two weeks in advance for forecasting was chosen to ensure a sufficient preparation response time for algae outbreak. The Nash–Sutcliffe coefficient of efficiency (R2) was between 0.84 and 0.99 for the training and over-fitting test data sets, while it was between 0.59 and 0.99 for the validation data set. To better respond to the algae outbreak, a number of management scenarios formed by orthogonal experimental design were modeled to assess the responses of chlorophyll-a and an optimal management scenario was identified, which can reduce chlorophyll-a by 23.8%. This study demonstrates that ANN model is potentially useful for forecasting eutrophication up to 2 weeks in advance. It also provides valuable information for the sound management of nutrient loads to reservoirs.

The Information Model for Hydrogeological Object and its Fuzzy-Deterministic Model

Study of fuzzydeterministic modeling matters of th e formation and exploitation of ground water intake processes. The issues of the situational analysis on the basis of fuzzydeterministic modeling results based on fuzzy parameters formalization of groundwater intake are abstracted. The results of computing experiments on the example of singlelayer Geofiltr ational systems are presented. Computing experiments are mentioned for the part applied in practice of formation flow sheet and groundwater resources exploitation. Given the acute shortage of water resources in the lease conditions, water represents a major source of potable water supply. Promising in this regard is the development of principles for establishing groundwater is abstracted complex hydrogeological and water conditions. In this paper we study projects withdrawals of groundwater is based on fuzzydeterministic approac h, i.e. on the basis of fuzzy set parameters , initial and boundary conditions geofiltration process. The algorithms of fuzzy parameters formalization of underground hydrosphere, the relationship abstraction of groundwater and its model. The algorithms of decision making in

Groundwater interaction assessment based on the large-scale mapping of geological and hydrogeological conditions in Moscow

Assessing the interaction between aquifers is crucial for estimating the extent of protection of the aquifer in Carboniferous limestone (which is the main source of potable water supply to Moscow area) against contaminants penetrating from the overlying aquifers. The presented approach to assessing groundwater interaction and protection is based on large-scale mapping of the geological and hydrogeological conditions in Moscow. The obtained results may be used for solving the problem of groundwater protection against contamination, as well as for planning the engineering activities in the city.

Assessment of endocrine disruptors – DDTs and DEHP (plasticizer) in source water: a case study from Selangor, Malaysia

The presence of endocrine disruptors in source water is of great concern because of their suspected adverse effects on humans, even when present at very low levels. As the main source of potable water supply, rivers in Malaysia are highly susceptible to contamination by various endocrine disruptors originating from anthropogenic activities. In this study, the contamination levels of 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) and its metabolites and di-(2-ethylhexyl) phthalate (DEHP) in rivers of Selangor were examined using gas chromatography-mass spectrometry. Samples were collected from sites representing source water for 18 drinking water treatment plants in Selangor between July 2008 and July 2009. DDT and its metabolites were detected in only 14% of the 192 samples analysed at levels ranging from 0.6 to 14.6 ng/L. Meanwhile DEHP was detected in 96.8% of the samples at levels ranging from below quantitation level (18 ng/L) to 970 ng/L. The detected levels of DDTs and DEHP were lower than the WHO and Malaysian Guidelines for Drinking Water Quality. Data obtained from this study should also serve as a reference point for future surveillance on these endocrine disruptors.

Studies of Ground water quality assessment at industrial belt of Kashipur, Uttarakhand, India

Pollution of ground water is one of the areas of major concern to environmentalists. Water quality is an index of health and well being of a society. Industrialisation, urbanisation and modern agriculture practices have direct impact on ground water resources. These factors influence the ground water quantitatively and qualitatively. Ground water is an important source of potable water supply for Kashipur as well as adjoined areas of the U S Nagar district for all purposes. Ten different locations were selected for the study and compared. Attempts were made to study and analyze the physico-chemical characteristics of the water. The parameters studied were temperature, pH, total alkalinity, total hardness, chloride, sulphate, total dissolved solids, calcium, magnesium and conductivity. By observing the result it can be concluded that the parameters which were taken for study the water quality are below the pollution level for ground water which satisfy the requirement for the use of various purposes like domestic, agricultural, industrial etc in Kashipur area.

Studies of surfacewater quality of the Kashipur, Uttarakhand, India

Pollution of water bodies is one of the areas of major concern to environmentalists. Water quality is an index of health and well being of a society. Industrialisation, urbanisation and modern agriculture practices have direct impact on water resources. These factors influence the water resources quantitatively and qualitatively. The study area selected were the Bahella river, Mahadev stream and Kosi river basin of Kashipur, Uttarakhand, India. The Bahellariver, Mahadev and Kosi river water is an important source of potable water supply for Kashipur as well as adjointed areas of the U S Nagar district for all purposes.The physico-chemical parameters like temperature, pH, turbidity, total hardness, alkalinity, BOD, COD, chloride, nitrate and phosphate and fluoride content in water of Bahella river, Mahadev stream and Kosi river were studied to ascertain the drinking and domestic as well as irrigation water supply in Kashipur area. In this present study water quality of Bahellariver, Mahadev stream and Kosi river is taken into account and Khokartalwater is found to be severely polluted with reference to these analyzed parameters.

Assessment of fluoride content in tropical surface soils used for crop cultivation.

Bongo district of the Upper East Region of Ghana relies on groundwater as the main source of potable water supply for domestic purposes. However, available literature indicated that groundwater in the area has elevated fluoride levels. Little work is done on fluoride contents in the soils of the area and its implication to plants and other living organisms. Hence the objectives of this study were to determine the level of fluoride (F) in cultivated soils and its implication to crops, since the soils form the essential medium for crops growth. Also to document fluoride concentrations in cropland soils in Ghana. Samples of selected cropland soils were collected at a depth ranged 1.0 cm to 30.0 cm and digested with aqua-regia, and analyzed for fluoride and calcium content using spectrophotometer DR/2000 and EDTA complexometric titration respectively. The mean pH of most of the soil samples ranged from 5.7 to 6.2, while the specific electrical conductivity ranged from 420.0 to 1735.0 μs/cm of soils used. The F content in the soils ranged from 219.26 to 1163.01 mgkg -1 DW. The ions bioavailability is controlled by physical and chemical characteristics of the soils. Although, this was the first study of its kind in the district it depicted that excess fluoride in water reported in the area has a relationship with the trend reported in this paper. Key words: Fluorine, laterite, Africa, fluorosis, toxicity, Bongo district, crops.

Distribution of Desalinated Seawaters: Are Corrosion Indicators Sufficient?

In anticipation of future water supply limitations, the Long Beach (Calif.) Water Department (LBWD) is conducting extensive research into desalinating seawater as a future potable water supply source. Corrosion potential is a central issue with regard to distributing any new water sources, particularly desalinated seawater. LBWD will ultimately perform a year-long pipe-loop study with 4-in. diameter, 20-ft long pipe sections with different blends of desalinated waters. To better define the scope of testing, blends from 100 percent distribution system water to 75 percent desalinated seawater (permeate) in 25 percent increments were evaluated through desktop calculations (corrosion indices) and bench-scale tests, including pipe-section (AWWA Standard C104) and marble testing. Various corrosion indices were calculated and compared to help guide the pipe-loop testing phase. Good correlations between the indices were obtained from the test results, and it appeared that modest adjustments (e.g., pH control) would allow blends up to 50 percent permeate to be used in the distribution system, but higher permeate blends would require more treatment. It was observed that use of lining (e.g., epoxy seal coating) in distribution system pipes could improve corrosion resistance. Initial lead and zinc release tests conducted with brass coupons for six weeks showed that higher permeate blends resulted in higher zinc and lead release, possibly requiring additional adjustment to mitigate the effects.

Groundwater balance in the Khor Arbaat basin, Red Sea State, eastern Sudan

The Khor Arbaat basin is the main source of potable water supply for the more than 750,000 inhabitants of Port Sudan, eastern Sudan. The variation in hydraulic conductivity and storage capacity is due to the heterogeneity of the sediments, which range from clay and silt to gravely sand and boulders. The water table rises during the summer and winter rainy seasons; it reaches its lowest level in the dry season. The storage capacity of the Khor Arbaat aquifer is estimated to be 21.75 × 106 m3. The annual recharge through the infiltration of flood water is about 1.93 × 106 m3. The groundwater recharge, calculated as underground inflow at the ‘upper gate’, is 1.33 × 105 m3/year. The total annual groundwater recharge is 2.06 × 106 m3. The annual discharge through underground outflow at the ‘lower gate’ (through which groundwater flows onto the coastal plain) is 3.29 × 105 m3/year. Groundwater discharge due to pumping from Khor Arbaat basin is 4.38 × 106 m3/year on average. The total annual groundwater discharge is about 4.7 × 106 m3. A deficit of 2.6 × 106 m3/year is calculated. Although the total annual discharge is twice the estimated annual recharge, additional groundwater flow from the fractured basement probably balances the annual groundwater budget since no decline is observed in the piezometric levels.