Simple Management Tools to Reduce Water Pumping Based on Hydrologic Probabilities and Supply Shortage Risk Quantification

摘要

The costs of transmission and management of water resources can be reduced with proper implementation and planning of operations. While many utilities rely on water that is pumped over large distances, the energy required for that pumping is costly, and the associated air emissions can be detrimental to the environment. As we begin to understand the water-energy nexus, the economic and environmental impacts of pumping have come under increased scrutiny. Municipalities and regional water authorities must develop tools for managing water supplies given the costs, limitations on resources, and impacts from resource consumption. Simple tools, based on hydrologic probabilities and a better understanding of the risk of water supply shortages, can be effective in minimizing energy needs to pump water. To assist the Brazos River Authority (BRA) with its water supply management and operations, models for transmission and operations improvements for their regional raw water system were developed. Two user-friendly, spreadsheet-based models were developed specifically for the BRA to provide guidance on mid- to long-range planning and real-time operations. The Planning Simulation model quantifies the risk of water supply shortages and reservoir spills based on the simulation of historical hydrologic conditions. The Operations Optimization model uses hydrologic forecasts, initial reservoir conditions, projected demands, and energy prices to provide guidance on 30-day operating plans. The simple format of each model allows the user to adjust many of the inputs, making it possible to evaluate several scenarios to assess risk and uncertainty. Using the two models together, it is possible to address hydrologic uncertainty and quantify supply shortage risks, to reduce water pumping over the long term and assist a utility in making informed decisions concerning their water supply management in real-time. Although these models contain a variety of useful functions for the BRA, this paper focuses on the potential uses, inputs, and outputs of these models as they pertain to developing operating plans to minimize the risk of water supply shortages and reduce operating costs as they relate to energy use. Additionally, this paper demonstrates how similar models can be developed by others to assist with planning and operations of their water supply systems.