Effects Of Reservoir Operation Research Articles

Patterns of internal nitrogen and phosphorus loadings in a cascade reservoir with a large water level gradient: Effects of reservoir operation and water depth

Internal nutrient loadings pose a high risk of being an additional N and P source, exacerbating eutrophication and deteriorating water quality. In this study, we selected the Daheiting Reservoir (DHTR) in North China, with a pronounced water level gradient, to investigate internal N and P loadings, estimate N and P fluxes across the sediment‒water interface based on the pore water profiles, and reveal the potential effects of water discharge from an upstream reservoir and high-intensity cage aquaculture on the risks of internal N and P release. The results indicated that DHTR presented with severe internal nutrient loadings, and the N and P fluxes showed significant spatiotemporal variations. NH4+−N and soluble reactive phosphorus (SRP) fluxes were higher in deep areas (averages of 26.14 and 9.9 mgm−2d−1, respectively) than in shallow areas near inflows (averages of 5.0 and 1.24 mgm−2d−1, respectively). Unexpectedly, the estimated NH4+−N and SRP fluxes were the lowest in summer (averages of 3.94 and 0.33 mgm−2d−1, respectively), which may have been influenced by seasonal thermal stratification and copious discharge from the hypolimnion of the upstream reservoir (Panjiakou Reservoir). Comparison of annual internal and external N and P loadings revealed that water discharge from the upstream Panjiakou Reservoir was the dominant source of N and P to the reservoir, contributing up to 83.6% of N input and 55.4% of P input. The internal P loading also contributed to water eutrophication to a great extent, accounting for 34.7% of the total P input. Our results highlight the impact of upstream reservoir discharge operation on downstream reservoir water quality and the importance of controlling the internal nutrient loading in cascade reservoirs, and further provide theoretical and practical foundations for the development of policies and strategies to conserve reservoir ecosystems.

Comparative analysis of routed flood frequency for reservoirs in parallel incorporating bivariate flood frequency and reservoir operation

AbstractFlood frequency is commonly defined by natural flood characteristics such as flood peak, volume and duration. However, for floods at reservoir site, reservoir operation will significantly alter the natural flood process and flood frequency. This article presents a framework of routed flood frequency which incorporates multi‐reservoir flood correlation and considers the effect of reservoir operation. Aggregated flood volume during reservoir operation has been adopted as indicator for the routed flood frequency curve (RFFC). A comparison has been made with a 62‐year series of historic flood inflows observed at two parallel reservoirs in Eastern China. By comparing the derived RFFC with traditional univariate and bivariate flood frequency results, it can be seen that the RFFC results provide a reasonable estimation of flood frequency. A sensitivity analysis indicated that the reservoir maximum release allocation has significant impact on RFFC, and a balanced allocation of flood peak can greatly decrease the overtopping risk. The “peak–peak” contour lines of the RFFC show that there are different flood combination zones which need different operation strategies in real‐time operation. Our findings improve the understanding of flood frequency concepts when considering the impact of reservoir operation and provide reference to manage real‐time reservoir operation.

Effects of reservoir operation and climate change on thermal stratification of a canyon-shaped reservoir, in northwest China

Abstract Thermal stratification has a significant impact on water quality and ecological characteristics. Reservoir operation and climate change have an effect on the thermal regime. The Jinpen Reservoir is a large canyon-shaped reservoir located in Shaanxi Province with a strong thermal stratification, which resulted in an anaerobic condition in the hypolimnion. We used a hydrodynamic module based on MIKE 3 to simulate the thermal structure of the Jinpen Reservoir and study the relationship between the thermal regime, reservoir operation and climate change. Based on the daily hydrological and climatic data from 2004 to 2013, we made 13 hypothetical simulated conditions that included extreme change of inflow volume, water level, air temperature, radiation, inflow water temperature and selective withdrawal to explore the effect of different factors on the thermal regime. The results showed that the period of thermal stratification, water column stability and surface water temperature were influenced by these factors. With the increase of air temperature, the simulation results indicated a stronger thermal stratification and a higher surface water temperature, which could cause water safety problems. Deep withdrawal could decrease water column stability and prompt water column mixing early, which could be used by reservoir managers to optimize the reservoir operation.

Improving Flood-Risk Analysis for Confluence Flooding Control Downstream Using Copula Monte Carlo Method

AbstractIn this study, a Copula Monte Carlo (CMC) method was proposed to improve flood risk for confluence flooding control downstream of a reservoir. The effects of reservoir operation and joint r...

Plunging inflows and the summer photic zone in reservoirs

Kinbasket and Revelstoke Reservoirs are part of the Columbia River system in eastern British Columbia, Canada. Hydroelectricity from these large reservoirs represents about 30% of the province's generation capacity. Of interest to water use planning is the effect of reservoir operation on pelagic productivity. We address one small part of this question, namely, the supply of nutrients carried by inflows that plunge below the photic zone during the summer. Using an idealized water balance for the photic zone, three cases are considered: (1) a shallow outlet, (2) a deep outlet, and (3) no outflow. For a shallow outlet, all inflow that plunges below the photic zone is upwelled into the photic zone on its way to the outlet. For a deep outlet, inflow that plunges below the photic zone will short circuit or pass directly to the outlet unless entrainment generates upwelling of the inflow into the photic zone. For a reservoir with no outflow, such as a reservoir that is filling, inflow that plunges below the photic zone remains at depth unless either entrainment or a bathymetric effect generates flow into the photic zone; nutrients are then released when the reservoir is drawn down, often in winter.

Paneth cells morphometry in human ileum: Effect of reservoir operation

Paneth cells morphometry in human ileum: Effect of reservoir operation

Jurisdictional Conflict in the Control Over Water Withdrawal for the Trent Canal

Water is a key resource for outdoor recreation. In many water allocation conflict situations, there is competition between recreation and other, non-recreation, users. However, in certain situations there may be competition between different recreation users. The paper discusses such a situation on the Trent Canal and its water storage reservoir-lakes. The conflict in the duty of water on the two components of the waterway is described, with particular emphasis on the externality effects of reservoir operation on reservoir recreation uses. The history of the conflict in the jurisdiction over water is outlined. Alternative solutions are reviewed.

Reservoir Operation for Recreation Usability

A model is developed for the operation of the reservoir feeder-lakes of the Trent Canal in Ontario, Canada. Using data which describe shoreline physiography and a scale which ranks shoreline recreation usability, coefficients are calculated which estimate the maximum water-level drawdown that a reservoir can tolerate. These tolerance coefficients, developed on study reservoirs, are then predicted to the rest of the reservoir-lakes in the Trent Canal system. Matrix conventions are used to associate drawdown tolerances to the relative and to the absolute storage capacity of the reservoirs. From the matrix, priority-ordering situations for reservoir operation are identified. The sequence of operation of reservoirs can be compared in various situations of reservoir water-storage depletion, and water requirements. The model allows shoreline physical recreation usability to be included in the rationale for reservoir operation, and it quantifies means whereby the effect of reservoir operation on recreation may be minimized.

Use of Models in Resolving Tidal Problems

A comprehensive hydraulic model of the Delaware Estuary is described, along with the adjustment and verification of the model. Also described are a number of uses made of the model that were not contemplated when the model was designed and constructed. These include, but are not limited to, studies of factors affecting saltwater intrusion; definition of flushing characteristics of the estuary; design of new navigation facilities; improved methods for waste disposal; the need for rehabilitating existing dikes; and the effects of reservoir operation on salt water intrusion.

Effects of Reservoir Operation on Stream Water Quality

Effects of Reservoir Operation on Stream Water Quality