scholarly journals Natural Pans as an Important Surface Water Resource in the Cuvelai Basin—Metrics for Storage Volume Calculations and Identification of Potential Augmentation Sites

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 177
Author(s):  
Robert Arendt ◽  
Christian Reinhardt-Imjela ◽  
Achim Schulte ◽  
Leona Faulstich ◽  
Tobias Ullmann ◽  
...  

Numerous ephemeral rivers and thousands of natural pans characterize the transboundary Iishana-System of the Cuvelai Basin between Namibia and Angola. After the rainy season, surface water stored in pans is often the only affordable water source for many people in rural areas. High inter- and intra-annual rainfall variations in this semiarid environment provoke years of extreme flood events and long periods of droughts. Thus, the issue of water availability is playing an increasingly important role in one of the most densely populated and fastest growing regions in southwestern Africa. Currently, there is no transnational approach to quantifying the potential storage and supply functions of the Iishana-System. To bridge these knowledge gaps and to increase the resilience of the local people’s livelihood, suitable pans for expansion as intermediate storage were identified and their metrics determined. Therefore, a modified Blue Spot Analysis was performed, based on the high-resolution TanDEM-X digital elevation model. Further, surface area–volume ratio calculations were accomplished for finding suitable augmentation sites in a first step. The potential water storage volume of more than 190,000 pans was calculated at 1.9 km3. Over 2200 pans were identified for potential expansion to facilitate increased water supply and flood protection in the future.

Author(s):  
Aseem Saxena

Fluorine is the most electronegative and most reactive halogen. Fluorine is 13th most common element on earth crust found in the form of fluoride. Concentration of fluoride below 1 mg/l are believed beneficial in the prevention of dental carries or tooth decay, but above 1.5mg/l, it increases the severity of the deadly diseases fluorosis, which is incurable in India. The whole study was conducted in Gorakhpur region to know about the concentration of fluoride, mainly in rural areas of the district. We have collected 64 drinking water samples from 9 blocks of the district in which we took 6 number of ground water samples from each block so total 54 number of samples were collected from the groundwater source and 8 number of samples were taken from surface water source. Out of 54 ground water samples, 36 numbers of samples were taken from India Mark-II hand pumps and rest 18 number of samples were taken from shallow depth hand pumps and tested to determine the concentration of fluoride. From our assessment we came to know that in this region the concentration of fluoride in groundwater ranges between 0.004 to 1.42mg/l, minimum value is found in the surface water source and the maximum value is found from the ground water source.The samples collected from both ground water and as well as surface water were taken from potable sources i.e. they are used for drinking purposes in daily routine. After the testing and analyzing the samples it is come to know that surface water has quite lower levels fluoride compare to ground water. The conclusion of this work is to give information about the concentration of fluoride in groundwater and surface water of the district.


2012 ◽  
Vol 66 (5) ◽  
pp. 1103-1109 ◽  
Author(s):  
Zenghu Qin ◽  
Mingwei Tong ◽  
Lin Kun

Due to the surface water in the upper reaches of Yangtze River in China containing large amounts of silt and algae, high content of microorganisms and suspended solids, the water in Yangtze River cannot be used for cooling a heat pump directly. In this paper, the possibility of using Yangtze River, which goes through Chongqing, a city in southwest China, as a heat source–sink was investigated. Water temperature and quality of the Yangtze River in the Chongqing area were analyzed and the performance of water source heat pump units in different sediment concentrations, turbidity and algae material conditions were tested experimentally, and the water quality standards, in particular surface water conditions, in the Yangtze River region that adapt to energy-efficient heat pumps were also proposed. The experimental results show that the coefficient of performance heat pump falls by 3.73% to the greatest extent, and the fouling resistance of cooling water in the heat exchanger increases up to 25.6% in different water conditions. When the sediment concentration and the turbidity in the river water are no more than 100 g/m3 and 50 NTU respectively, the performance of the heat pump is better, which can be used as a suitable river water quality standard for river water source heat pumps.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 665
Author(s):  
Chanchai Petpongpan ◽  
Chaiwat Ekkawatpanit ◽  
Supattra Visessri ◽  
Duangrudee Kositgittiwong

Due to a continuous increase in global temperature, the climate has been changing without sign of alleviation. An increase in the air temperature has caused changes in the hydrologic cycle, which have been followed by several emergencies of natural extreme events around the world. Thailand is one of the countries that has incurred a huge loss in assets and lives from the extreme flood and drought events, especially in the northern part. Therefore, the purpose of this study was to assess the hydrological regime in the Yom and Nan River basins, affected by climate change as well as the possibility of extreme floods and droughts. The hydrological processes of the study areas were generated via the physically-based hydrological model, namely the Soil and Water Assessment Tool (SWAT) model. The projected climate conditions were dependent on the outputs of the Global Climate Models (GCMs) as the Representative Concentration Pathways (RCPs) 2.6 and 8.5 between 2021 and 2095. Results show that the average air temperature, annual rainfall, and annual runoff will be significantly increased in the intermediate future (2046–2070) onwards, especially under RCP 8.5. According to the Flow Duration Curve and return period of peak discharge, there are fluctuating trends in the occurrence of extreme floods and drought events under RCP 2.6 from the future (2021–2045) to the far future (2071–2095). However, under RCP 8.5, the extreme flood and drought events seem to be more severe. The probability of extreme flood remains constant from the reference period to the near future, then rises dramatically in the intermediate and the far future. The intensity of extreme droughts will be increased in the near future and decreased in the intermediate future due to high annual rainfall, then tending to have an upward trend in the far future.


2011 ◽  
Vol 15 (8) ◽  
pp. 2509-2518 ◽  
Author(s):  
A. Guevara-Escobar ◽  
M. Cervantes-Jiménez ◽  
H. Suzán-Azpiri ◽  
E. González-Sosa ◽  
L. Hernández-Sandoval ◽  
...  

Abstract. Interception losses are a major influence in the water yield of vegetated areas. For most storms, rain interception results in less water reaching the ground. However, fog interception can increase the overall water storage capacity of the vegetation and once the storage is exceeded, fog drip is a common hydrological input. Fog interception is disregarded in water budgets of semiarid regions, but for some plant communities, it could be a mechanism offsetting evaporation losses. Tillandsia recurvata is a cosmopolitan epiphyte adapted to arid habitats where fog may be an important water source. Therefore, the interception storage capacity by T. recurvata was measured in controlled conditions and applying simulated rain or fog. Juvenile, vegetative specimens were used to determine the potential upperbound storage capacities. The storage capacity was proportional to dry weight mass. Interception storage capacity (Cmin) was 0.19 and 0.56 mm for rainfall and fog respectively. The coefficients obtained in the laboratory were used together with biomass measurements for T. recurvata in a xeric scrub to calculate the depth of water intercepted by rain. T. recurvata contributed 20 % to the rain interception capacity of their shrub hosts: Acacia farnesiana and Prosopis laevigata and; also potentially intercepted 4.8 % of the annual rainfall. Nocturnal stomatic opening in T. recurvata is not only relevant for CO2 but for water vapor, as suggested by the higher weight change of specimens wetted with fog for 1 h at dark in comparison to those wetted during daylight (543 ± 77 vs. 325 ± 56 mg, p = 0.048). The storage capacity of T. recurvata leaf surfaces could increase the amount of water available for evaporation, but as this species colonise montane forests, the effect could be negative on water recharge, because potential storage capacity is very high, in the laboratory experiments it took up to 12 h at a rate of 0.26 l h−1 to reach saturation conditions when fog was applied.


2012 ◽  
Vol 518-523 ◽  
pp. 4126-4129
Author(s):  
Zhen Hua Liu

Source of water is the beginning of rural drinking water projects, safe water source is the key to rural drinking water safety. Status of rural drinking water source in china and laws and regulations on rural water conservation were analyzed. The population of centralized water supply accounts for 51% of the total population in rural areas in 2008, centralized water supply 49%. Groundwater source accounts for 57% of the population of centralized water supply projects in rural areas in 2008, surface water sources 43%. China has a relatively sound legal system of drinking water source, including basic law, general law, administrative regulations, local regulations.The paper draws a conclusion that sources of drinking water in rural areas is mainly groundwater, water conservation is short of specific laws and regulations and not suitable for rural area,it is necessary to improve laws and regulations on rural water conservation, government must assume responsibility for rural water conservation, especially financial investment and public policy support.


2020 ◽  
Vol 8 (6) ◽  
pp. 2509-2512

Catchments are most important for the purpose of practicing irrigation and recharging groundwater by collecting water during the rainy season so that the nearby land will be in surplus quantity of groundwater due to the continues percolation of water from the catchments, even the stored water in the form of catchments will be used as an alternative water source for other requirements apart from the irrigation practices such as for industries and other developmental activities taking place nearby the catchments. Year by year it was noticed that in the world scenario the pollutant concentration is keep on increasing especially water and air pollution due to the excessive load of population that is increasing from the rural to urban areas [10]. Coming to water pollution the major portion of pollution is increasing in the surface water bodies [4] due to various activities like surface runoff, intentionally releasing of untreated effluents from the nearby industries into the catchments [8] and the agricultural runoff etc, whatever the reason there is an immediate need and an emergency to monitor these catchments as the average rainfall is gradually decreasing due to the changing climatic conditions like global warming which leads to the reduced availability of water in the surface water bodies at the other side the existing water is being contaminated [5] by the activities of nearby people. The impact will be severe when the same situation continues in the days to come where the living standards of the people will be decreased at a notable level and the impact will be much more severe on the irrigated land which depends on the catchments. The study has done at Kolleru Lake in west godavari district, Andhra Pradesh. Collected Six Water samples from six locations around the lake for analysis [7] and then the results of the analysis compared with Central Pollution Control Board 1979and Indian standards 1982 guidelines for water in the surface water bodies to find out the present scenario of lake water.


PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243836
Author(s):  
Mekuria Asnakew Asfaw ◽  
Teklu Wegayehu ◽  
Tigist Gezmu ◽  
Alemayehu Bekele ◽  
Zeleke Hailemariam ◽  
...  

Background Pre-school aged children (PSAC) are highly affected by soil-transmitted helminths (STH), particularly in areas where water, sanitation, and hygiene (WASH) are inadequate. Context-specific evidence on determinants of STH infections in PSAC has not been well established in the study area. This study, therefore, aimed to fill these gaps in Gamo Gofa zone, Southern Ethiopia. Methods A community-based unmatched case-control study, nested in a cross-sectional survey, was conducted in January 2019. Cases and controls were identified based on any STH infection status using the Kato-Katz technique in stool sample examination. Data on social, demographic, economic, behavioral, and WASH related variables were collected from primary caregivers of children using pre-tested questionnaire. Determinants of STH infections were identified using multivariable logistic regression model using SPSS version 25. Results A total of 1206 PSAC (402 cases and 804 controls) participated in this study. Our study showed that the odds of STH infection were lowest among PSAC living in urban areas (AOR = 0.55, 95% CI: 0.39–0.79), among those from households with safe water source (AOR = 0.67, 95% CI: 0.47–0.0.93), and in those PSAC from households with shorter distance from water source (<30 minutes) (AOR = 0.51, 95% CI: 0.39–0.67). On the other hand, the odds of STH infection were highest among PSAC from households that had no functional hand washing facility (AOR = 1.36, 95% CI: 1.04–1.77), in those PSAC from households that had unclean latrine (AOR: 1.82, 95% CI: 1.19–2.78), and among those PSAC under caregivers who had lower score (≤5) on knowledge related to STH transmission (AOR = 1.85, 95% CI: 1.13–3.01). Conclusions Given efforts required eliminating STH by 2030; the existing preventive chemotherapy intervention should be substantially strengthened with WASH and behavioral interventions. Thus, an urgent call for action is required to integrate context-specific interventions, particularly in rural areas.


2020 ◽  
pp. 70-77
Author(s):  
L.A. Deryabkina ◽  
◽  
B.I. Marchenko ◽  
N.K. Plugotarenko ◽  
A.I. Yukhno ◽  
...  

In most Russian regions there is still a pressing issue related to providing population with high quality and safe drinking water. Up to now, chlorination has been the primary technique applied to disinfect drinking water as it is highly efficient, reliable, and relatively cheap. However, when chlorine is used to disinfect natural water that contains organic pollutants, it results in risks of by-products occurrence. These products are trihalomethanes, epigenetic carcinogenesis promoters that cause elevated carcinogenic risks under oral, inhalation, and subcutaneous exposure. Our research goal was to hygienically assess efficiency of pre-ammonization applied in water treatment procedures in order to prevent occurrence of carcinogenic organic chlorine compounds during chlorination and to minimize carcinogenic risks. We determined trihalomethanes and residual chlorine contents in model samples of natural water taken from a surface water source after chlorination with different doses of chlorine. We examined 52 pair parallel samples that had undergone pre-ammonization with ammonia sulfate and control ones. Trihalomethanes concentrations were determined in model water samples with gas-liquid chromatography. Basing on the results obtained via experiments on laboratory chlorination of river water, we determined quantitative characteristics and built regression models showing dependence between concentrations of organic chlorine compounds occurring due to chlorination (chloroform, dichlorobrommethane, dibromchloromethane) and chlorine doses and preammonization parameters. It was established that pre-ammonization was the most efficient in terms of preventing trihalomethanes occurrence under such disinfection modes when contents of residual active chlorine didn’t exceed recommended levels (0.8–1.2 mg/L). Basic ways to minimize carcinogenic risks caused by trihalomethanes are systemic control over their contents in drinking water during social and hygienic monitoring procedures; preliminary ammonization of water taken from surface water sources; prevention of unjustified hyper-chlorination; preliminary deep purification of initial water; disinfection with ultrasound radiation instead of preliminary chlorination; etc.


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