H33G-1704
Integrated Watershed Management to Rehabilitate the Distorded Hydrologic Cycle in a Korean Urban Region
Many urbanized watersheds suffer from streamflow depletion and poor stream quality, which often negatively affects related factors such as in-stream and near-stream ecologic integrity and water supply. But any watershed management which does not consider all potential risks is not proper since all hydrological components are closely related. Therefore this study has developed and applied a ten-step integrated watershed management (IWM) procedure to sustainably rehabilitate distorted hydrologic cycles due to urbanization. Step 1 of this procedure is understanding the watershed component and processes. This study proposes not only water quantity/quality monitoring but also continuous water quantity/quality simulation and estimation of annual pollutant loads from unit loads of all landuses. Step 2 is quantifying the watershed problem as potential flood damage (PFD), potential streamflow depletion (PSD), potential water quality deterioration (PWQD) and watershed evaluation index (WEI). All indicators are selected from the sustainability concept, Pressure-State- Response (PSR) model. All weights are estimated by Analytic Hierarchy Process (AHP). Four indices are calculated using composite programming, a kind of multicritera decision making technque. In Step 3 residents' preference on management objectives which consists of flood damage mitigation, prevention of streamflow depletion, and water quality enhancement are quantified. WEI can be recalculated using these values. Step 4 requires one to set the specific goals and objectives based on the results from Step 2 and 3. Objectives can include spatial flood allocation, instreamflow requirement and total maximum daily load (TMDL). Step 5 and 6 are developing all possible alternatives and to eliminate the infeasible. Step 7 is analyzing the effectiveness of all remaining feasible alternatives. The criteria of water quantity are presented as changed lowflow(Q275) and drought flow(Q355) of flow duration curve and number of days to satisfy the instreamflow requirement. Also the criteria of water quality are proposed as changed average BOD concentration and total daily loads and number of days to satisfy the TMDL. Step 8 involves the calculation of AEI using various MCDM techniques. The indicators of AEI are obtained by the sustainability concept, Drivers-Pressure-State-Impact-Response (DPSIR), an improved PSR model. All previous results are used in this step. Step 9 is estimating the benefit and cost of alternatives. Discrete Willingness To Pay (WTP) for the specific improvement of some current watershed conditions are estimated by the choice experiment method which is an economic valuation with stated presence techniques. WTPs of specific alternatives are calculated by combining AEI and choice experiment results. Therefore, the benefit of alternatives can be obtained by multiplying WTP and total household value of the sub-watershed. Finally in Step 10 the final alternatives comparing the net benefit and BC ratio are determined. Final alternatives derived from the proposed IWM procedure should not be carried out immediately but be discussed by stakeholders and decision makers. However, since plans obtained from the elaborated analyses reflect even sustainability concept, these alternatives can be apt to be accepted comparatively. This ten-step procedure will be helpful in making decision support system for sustainable IWM.
H33G-1705
Groundwater Management Model to Meet the Goals of Water Supply and Ecological Baseflow
Groundwater is important for water supply and stream baseflow during dry period in Taiwan. Ecological baseflow is an essential element to maintain the sustainability of the stream ecosystem. How to maintain ecological baseflow and to estimate allowable groundwater withdraws for water supply system becomes an essential issue. On the premise that satisfies both ecological baseflow and water supply, a simulation-optimization model is developed to allocate groundwater pumpings among an area which is divided into several zones. This study will apply MODFLOW model to construct a pumping-drawdown response matrix, and further develop an optimization model to optimize maximal pumping and to determine allowable withdraw for each zone. Both land uses and equality are considered in the discussion. In this study, we expect that through the research process, it can allocate and utilize the surplus groundwater resource in the study area, and then achieve effective management of groundwater resource.
H33G-1706
Reservoir Flood Operation Planning Using Penalty-Type Genetic Algorithm
The purposes of a reservoir flood control operation are to decrease the flood peak stage downstream and to store enough floodwaters in the end of operation. In this study, we investigate rational operation decisions through formulating a reservoir flood control optimization model with linguistic description of requirements and regulations, and using the genetic algorithm (GA) to search a global optimum of a mixture of mathematical and nonmathematical formulations. Due to the great number of constraints and flood control requirements, the proper penalty strategy is proposed to guide the GA searching process. The proposed approach is applied to the Shihmen reservoir in North Taiwan for finding the rational (optimal) hydrograph as a case study. To demonstrate the effectiveness of the proposed approach, the simplex method was performed. The results demonstrated that a penalty-type genetic algorithm can be satisfactorily used in reservoir flood control planning to provide rational hydrographs for two purposes of flood operation, reducing flood damage and increasing final storage.
H33G-1707
Sustainable Water and Energy in Gaza Strip
Shortage of fresh water is a common problem in different areas of the world including the Middle East. Desalination of seawater and brackish water is the cheapest way to obtain fresh water in many regions. This research focuses on the situation in Gaza Strip where there is a severe shortage in the energy and water supply. The depletion of fresh water supplies and lack of wastewater treatments result in environmental problems. A solar powered cogeneration plant producing water and energy is proposed to be a suitable solution for Gaza Strip. Solar energy, using Concentrating Solar thermal Power (CSP) technologies, is used to produce electricity by a steam cycle power plant. Then the steam is directed to a desalination plant where it is used to heat the seawater to obtain freshwater. The main objective of this research is to outline a solution for the water problems in Gaza Strip, which includes a cogeneration (power and water) solar powered plant. The research includes four specific objectives: 1- an environmental and economic comparison between solar and fossil fuel energies; 2- technical details for the cogeneration plant; 3- cost and funding, 4- the benefits.
H33G-1708
Polyacrylamide Transport in Water Delivery Canals
Linear, anionic polyacrylamide (PAM) is being considered in the western United States as a technology to reduce seepage in unlined water delivery canals. A broad laboratory and field testing program has been undertaken to understand the benefits and potential environmental impacts of PAM use. The ability to predict the fate and transport of PAM in water delivery canals could prove to be a useful planning tool for PAM application. However, one key area of uncertainty of this type of canal treatment is the hydration, reaction, and settling rates of PAM after the dry powder is added to the canal water. In this study, we have developed a model that incorporates a number of known physical and chemical processes that can affect PAM transport, such as convection, dispersion, dissolution, flocculation, and settling, while solving the governing convection-dispersion transport equation. The model uses a mixed analytical and advanced numerical approach, and implements a transient partitioning of PAM mass between the canal water, the substrate soil, and potentially to open water bodies downstream of the application point. All source terms are modeled based on physical and chemical mechanisms as well as laboratory or field determined parameters. To more closely simulate field treatment of some canals, where PAM application moves upstream in time, the model is capable of implementing either a fixed or mobile upper boundary. In the latter treatment, the PAM can be added discretely or continuously in both time and space. A number of test situations have been simulated thus far, including theoretical and hypothetical cases for a wide range of conditions. The model also performed well when predicting PAM concentrations from a full-scale canal treatment experiment. The model provides a useful tool for predicting PAM fate and transport in water delivery canals, and therefore can play an important role in evaluating the efficacy of PAM application for water resources management. Moreover, the model could also be used to simulate the transport of many other reactive particle in open channels, thereby widening its potential use to a lot of environmental situations.