Hydrological optimization
Encyclopedia
Hydrological optimization applies mathematical optimization
techniques (such as linear programming
) to water-related problems. These problems may be for surface water
, groundwater
, or the combination. The work is interdisciplinary, and may be done by hydrologists, civil engineer
s, environmental engineers, and operations research
ers.
Groundwater and surface water flows can be studied with hydrologic simulation
. A typical program used for this work is MODFLOW
. However, simulation models cannot easily help make management decisions, as simulation is descriptive. Simulation shows what would happen given a certain set of conditions. Optimization, by contrast, finds the best solution for a set of conditions. Optimization models have three parts: (1) an objective, such as "Minimize cost", (2) decision variables, which correspond to the options available to management, and (3) constraints, which describe the technical or physical requirements imposed on the options.
To use hydrological optimization, a simulation is run to find constraint coefficients for the optimization. An engineer or manager can then add costs or benefits associated with a set of possible decisions, and solve the optimization model to find the best solution.
Examples of problems solved with hydrological optimization:
- Contaminant remediation in aquifers. The decision problem is where to locate wells, and choose a pumping rate, to minimize the cost to prevent spread of a contaminant. The constraints are associated with the hydrogeological flows.
- Maximizing well abstraction subject to environmental flow constraints (Wagner 1995, Feyen and Gorelick 2005). The goal is to measure the effects of each user's water use on other users and on the environment, as accurately as possible, and then optimize over the available feasible solutions.
- Hydrological optimization is now being proposed for use with smart market
s for water-related resources.
Optimization (mathematics)
In mathematics, computational science, or management science, mathematical optimization refers to the selection of a best element from some set of available alternatives....
techniques (such as linear programming
Linear programming
Linear programming is a mathematical method for determining a way to achieve the best outcome in a given mathematical model for some list of requirements represented as linear relationships...
) to water-related problems. These problems may be for surface water
Surface water
Surface water is water collecting on the ground or in a stream, river, lake, wetland, or ocean; it is related to water collecting as groundwater or atmospheric water....
, groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
, or the combination. The work is interdisciplinary, and may be done by hydrologists, civil engineer
Civil engineer
A civil engineer is a person who practices civil engineering; the application of planning, designing, constructing, maintaining, and operating infrastructures while protecting the public and environmental health, as well as improving existing infrastructures that have been neglected.Originally, a...
s, environmental engineers, and operations research
Operations research
Operations research is an interdisciplinary mathematical science that focuses on the effective use of technology by organizations...
ers.
Groundwater and surface water flows can be studied with hydrologic simulation
Simulation
Simulation is the imitation of some real thing available, state of affairs, or process. The act of simulating something generally entails representing certain key characteristics or behaviours of a selected physical or abstract system....
. A typical program used for this work is MODFLOW
MODFLOW
MODFLOW is the U.S. Geological Survey modular finite-difference flow model, which is a computer code that solves the groundwater flow equation. The program is used by hydrogeologists to simulate the flow of groundwater through aquifers...
. However, simulation models cannot easily help make management decisions, as simulation is descriptive. Simulation shows what would happen given a certain set of conditions. Optimization, by contrast, finds the best solution for a set of conditions. Optimization models have three parts: (1) an objective, such as "Minimize cost", (2) decision variables, which correspond to the options available to management, and (3) constraints, which describe the technical or physical requirements imposed on the options.
To use hydrological optimization, a simulation is run to find constraint coefficients for the optimization. An engineer or manager can then add costs or benefits associated with a set of possible decisions, and solve the optimization model to find the best solution.
Examples of problems solved with hydrological optimization:
- Contaminant remediation in aquifers. The decision problem is where to locate wells, and choose a pumping rate, to minimize the cost to prevent spread of a contaminant. The constraints are associated with the hydrogeological flows.
- Maximizing well abstraction subject to environmental flow constraints (Wagner 1995, Feyen and Gorelick 2005). The goal is to measure the effects of each user's water use on other users and on the environment, as accurately as possible, and then optimize over the available feasible solutions.
- Hydrological optimization is now being proposed for use with smart market
Smart market
A "smart market" is a periodic auction which is cleared by the operations research technique of mathematical optimization, such as linear programming. The smart market is operated by a market manager. Trades are not bilateral, between pairs of people, but rather to or from a pool...
s for water-related resources.
See also
- Water in CaliforniaWater in CaliforniaCalifornia’s interconnected water system serves over 30 million people and irrigates over of farmland. As the world’s largest, most productive, and most controversial water system, it manages over of water per year.- Sources of water :...
- Integrated Water Resources ManagementIntegrated Water Resources ManagementIntegrated Water Resources Management has been defined by the Technical Committee of the Global Water Partnership as "a process which promotes the coordinated development and management of water, land...
- Drainage researchDrainage researchDrainage research is the study of agricultural drainage systems and their effects to arrive at optimal system design.- Aspects to be covered :...
- MOHID LandMOHID LandMOHID Land is the hydrology module within the three-dimensional MOHID Water Modelling System. MOHID is an integrated system for water flow, consisting of three main modules: Water for three-dimensional fluid dynamics, Land for hydrology and Soil for groundwater flow...
- Geographic information systemGeographic Information SystemA geographic information system, geographical information science, or geospatial information studies is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographically referenced data...