Volume 2 Issue 3
Authors: Velimir V. Vesselinov; Dylan R. Harp
Abstract: It has been previously observed that during a pumping test in heterogeneous media, drawdown data from different time periods collected at a single location produce different estimates of aquifer properties and that Theis type-curve inferences are more variable than late-time Cooper-Jacob inferences. In order to obtain estimates of aquifer properties from highly transient drawdown data using the Theis solution, it is necessary to account for this behavior. We present an approach that utilizes an exponential functional form to represent Theis parameter behavior resulting from the spatial propagation of a cone of depression. This approach allows the use of transient data consisting of early-time drawdown data to obtain late-time convergent Theis parameters consistent with Cooper-Jacob method inferences. We demonstrate the approach on a multi-year dataset consisting of multi-well transient water-level observations due to transient multi-well water-supply pumping. Based on previous research, transmissivities associated with each of the pumping wells are required to converge to a single value, while storativities are allowed to converge to distinct values.
Keywords: Pumping Test; Heterogeneous; Effective
Authors: Xu Liang; Tyler W. Davis
Abstract: A field study along a grass-covered hillside in south-western Pennsylvania revealed diel fluctuations in soil moisture measurements resembling hydraulically redistributed water. Further analysis of the measurements over a summer and winter season supports this finding. The observations are analyzed for possible influences due to soil temperature. Temperature influence on the EC-5 soil moisture sensor readings appears to be present at 5 cm in the form of a correlated pattern with temperature, i.e., an increase in soil moisture with temperature. An inversely correlated pattern, i.e., an increase in soil moisture during the nighttime, shown at 40 and 62 cm is present during the summer dry-down periods and absent during the wet winter season. Given the available data, it is likely that more than temperature is affecting the measurements. Significant amounts of water are found to be redistributed compared to amounts transpired (20–60%). Continued research on this subject is recommended.
Keywords: Hydraulic Redistribution; Soil Moisture Observations; Soil Moisture Sensor Measurements
Authors: Dr. T K Lohani; T C Samant; R.S. Patnaik; K.P. Dash
Abstract: The type of diversity of drainage problems requires a clear understanding of the purpose for designing a drainage scheme. Various factors confronted and some may be opposite to each other as regards to their merits are concerned. It is difficult to accommodate all factors in final design. The combination of various factors depending upon their suitability of a particular drainage area gives the design to its final shape. The benefit cost factor is a major criterion since a perfect technical solution will cost very high. The main aim of this study is to devise an effective drainage system of least cost. Before designing it is necessary to decide the rate at which excess water should be removed from the agricultural field. If the rate is too low, crops may sustain injury due to submergence and if too high, the cost of drainage scheme will go up. Therefore, evaluation of design run-off is most important in any drainage scheme. In this regard Mahanadi-Chitrotpala-Luna DOAB has been studied to assess the effective run-off. Its basic aim is to indicate how to obtain the highest benefits from the given resources. Economic evaluation of this project calls for a comparison of benefits and costs. In the field, it is very difficult to get a stable section of a drain which can carry a design discharge. It is observed that, the drain of bigger size tends to deteriorate fast as they do not carry design discharge in the study area. On the other hand, the drains of the smaller size, than the design section remain in better condition and can carry occasionally higher discharge. As per Mc. Maths formula the discharge for smaller catchments is restricted to 6 km2 and the design discharge is 40 % of 15 km2 whereas for larger catchments, Cypress-Creek formula with coefficient (C) 55 gives the result more realistic and is recommended for acceptance in the study area. This absolutely clears the benefit of doubt regarding cost factor and other technical implications.
Keywords: DOAB; Drainage; Mc. Maths Formula; Cypress-Creek Formula; Water Logging
Authors: Thewodros G. Mamo; Ilan Juran; Isam Shahrour
Abstract: Today’s big city water utility companies are experiencing high level of water loss due to various problems in covering a large scale of water supply pipeline networks, therefore any significant improvement of water loss prevention from supply network to treatment plant would require an apprehends stochastic nature of historical water demand and supply pattern. For this reason urban water demand forecasting is one of key important parameters used when water utility companies are trying to find more efficient and robust ways of supplying water for a large number of urban consumers. Water demand forecasting also plays a significant role in managing and planning water supply operations and water conservation and optimization strategies. However, traditional forecasting approaches based on a set of deterministic design capacity factors or using demand forecasting algorithms without evaluating the relationship between supply reliability in response to the stochastic nature of historical water consumption data and supply pattern often become misleading due to the inability to sufficiently forecast forthcoming events and lack of relevant historical pattern and data. This paper presents an analysis and water demand forecasting demonstration using the stochastic nature of short term historical water demand and supply Pattern for Lille University Z6 pipeline networks research area in France.
Keywords: Urban Water Demand; Time series (AR1); Forecasting; Stochastic Simulation; Historic Demand Pattern