quality management of groundwater resources in aghala
نویسندگان
چکیده
introduction water quality refers to the chemical, physical and biological characteristics of water. it is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. it is most frequently used by reference to a set of standards against which compliance can be assessed. the most common standards used to assess water quality are related to health of ecosystems, safety of human contact and drinking water. some studies have focused only on chlorides alone without considering the nitrates. reports of harmful effects for human health have been reported only for nitrates. therefore, reducing nitrates level below the specifications of who may yield ‘‘healthy’’ water. on the other hand, high levels of chlorides may render the water undrinkable due to its salinity. in other words, focusing only on chlorides would not solve the problem since people would rather drink non-salty water than water with high level of nitrates which is proved to be dangerous in terms of health. this research considers both nitrates and chlorides using goal programming, which provides a way of striving toward more than one objective function simultaneously. it seeks to establish a specific numeric goal for each of the objectives, and then seeks for a solution that minimizes the weighted sum of deviations of objective functions from their corresponding goals. the purpose of this study is to achieve an optimal combination for drinking water according to the world health organization standards and the maximum desirable standard of groundwater in the study area of aghala using weighted goal programming model. goal programming formulation: assuming that we have () wells, the amount of chlorides in the th well is () mg/l and the amount of nitrates is ( ) mg/l. moreover, the ith well can discharge the amount of s () at a given operational level. since the levels of nitrates and chlorides are high in some wells and low in others, it is known that mixing of certain proportions from given wells will help achieve the required objective. it is also assumed that there are () reservoirs (destinations) each of which can accommodate a certain amount of water that satisfies the demand of the specific region. let () represent the demand required for reservoir () and ()the amount of water () discharged from well () to reservoir (). the maximum allowable amount of chlorides per liter (who standard) is (), while the maximum allowable amount of nitrates according to who standards is (). therefore, the writers formulated a goal programming model of optimal water allocation in aghala region as follows (all the symbols are difided in the first table of the text): a) objective function b) well capacity constraints c) reservoirs capacity and demand constraints d) balance constraint amoang the nodes e) groundwater reservoirs capacity f) air reservoirs capacity ( g) chlorides balance constraints h) nitrates balance constraints i) all variables are ≥0. the set of constraints in eq. (b) guarantees that the total amount of the discharged water from certain wells does not exceed their capacity. while the constraints in eq. (c) require that the amount of water supplied to a given reservoir from given wells does not exceed the capacity of that reservoir. eq. (d) represents balance constraint among the nodes. eqs. (e) and (f), respectively, represent groundwater and air reservoir capacity in the case study area. eqs. (g) and (h), respectively, also represent the chlorides and nitrates balance before and after mixing. the assumption in the (chlorides/nitrates) balance constraints is that there are no reactions due to water mixing which may decrease the amounts of both elements under study. therefore, this assumption, though approximate, guarantees that the levels of nitrates and chlorides can always be equal to or less than the amount determined by world health organization (who). moreover, it is assumed that the system experiences no loss of nitrates as shown by preliminary experiments. in other words, the results will always be on the conservative side. solution of the above model results in obtaining combination of wells and the amounts of water from each well. results and discussion this research describes a mathematic programming model dealing with achieving an optimum mixture of water from different underground wells, each having different amounts of nitrates and chlorides. the amounts of chlorides and nitrates in each of the wells may be higher or lower than the world health organization (who) standards. therefore, the optimum mixture would be the one that meets who standard which is 250 mg/l for chlorides and 50 mg/l for nitrates. a goal programming model was developed to identify the combination of wells along with the amounts of water from each well that upon mixing would result in minimizing the deviation of the amounts of chlorides and nitrates from the standards of who. application of the proposed model to the real case example (aghala region) demonstrates the reliability and flexibility of the model. the most important results of this study showed that according to the who standards and the difference elements of each the wells, water withdrawal of the combination of the wells is an appropriate way to allocation of reservoir water. the purpose of this study is to achieve an optimal combination for drinking water according to the who standards and the maximum desirable standards of groundwater in the aghala region using weighted goal programming model. in this region, there are 4 groundwater wells, 6 air reservoir and 2 ground reservoir (to save and transport water to the air reservoir) to supply drinking water for 17 villages. the results of this study also showed that the amount of water withdrawal in the wells in the who standard and maximum desirable standard is different. the most water withdrawal in the condition of who standards and maximum acceptable standard is belonging to well number 3 and the least withdrawal amount is belonging to well number 1 due to high concentration of nitrate in this well. according to the results in the maximum acceptable standard, there was not water withdrawal of well number 3 because of the high concentration of nitrate in this well. therefore, according to the who standards and the difference elements of each the wells, water withdrawal of the combination of the wells is recommended. finally, wells with levels of nitrates and chlorides that are highly intolerable can be used for drinking purposes upon mixing.
منابع مشابه
Investigation of quantity and quality variations groundwater resources Shiraz Plain
It is a basic process, distinguishing of water based on quantity and quality properties and condition of it reach for consuming optimum. It has been to descent processes the level of underground water according to simple hydrograph of Shiraz plain in statistical period of 1993-2011 that totally the level of underground water has been decreasing about 5.98 meters. It has been decreased the quali...
متن کاملLogic programming in groundwater resources management
Artificial intelligence techniques can be used to solve problems using a heuristic approach. This paper deals with a model able to verify whether there is groundwater in a given place, the quantity available and its quality. The system has been implemented in the logic programming language Prolog and runs on a personal computer under MS-DOS. The knowledge base has been constructed using degrees...
متن کاملEvaluation of Quality Changes in the Groundwater Resources and IRWQIGC Upstream of Zayandehrood Dam
Understanding the quality of groundwater resources, which are the largest available freshwater reservoir, is one of the needs in planning and developing water resources. The purpose of this research was to study the quality changes of groundwater resources in the upstream aquifers of Zayandehrood Dam (1995-2016) and to evaluate water quality in terms of drinking and agricultural consumption and...
متن کاملapplication of game theory for groundwater resources management of atrak
abstract atrak basin is an agricultural area in north khorasan province that the most farmers are using from groundwater resources for irrigation their crops. decreasing rainfall in recent years in this area, competition between urban, agriculture and industrial consumers has increased for water acquisition. in present study, game theory was applied for groundwater resources management of atrak...
متن کاملSustainable Management of Groundwater Resources Using Multi-Criteria Programming (A Case Study of Kashmar Plain)
Frequent droughts and their consequences result in the loss of groundwater, the deficiency of nutrients, the drying of surface water resources, and substantially more exploitation of the groundwater resources, which, altogether, cause the mobilization of saline waters to groundwater tables. This will impair the capacity of the aquifers and the quality of the water. The VIKOR method was applied ...
متن کاملValuation of Groundwater Resources in Agricultural uses: Bijar,Iran
The agricultural sector is of particular importance in the city of Bijar. Thus, the economic value perunit of water applid to the side effects of excessive groundwater resources in this area has a utmostimportance. Payment for estimation of water on a suitable production function was estimated revenueproducers. Therefore in this study to estimate the economic value of water resources in agricul...
متن کاملمنابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
محیط شناسیجلد ۴۰، شماره ۳، صفحات ۷۷۵-۷۸۶
کلمات کلیدی
میزبانی شده توسط پلتفرم ابری doprax.com
copyright © 2015-2023