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A hydrologic model helps to estimate the response of an aquifer system to a given set of conditions. Field measurements and experiments to estimate the response to these conditions can be very costly and time consuming. In most cases field measurements are not available simply because the water management strategy being evaluated has not yet been implemented. Models are developed to consolidate available information and provide a preliminary picture of the aquifer system. The cost of developing a model is insignificant compared to the value added to the decision-making process. This savings is especially valuable as the economic and environmental stakes of water management decisions are extremely high. The schematic presented below outlines the key model building steps and their utility.
An aquifer system model is always useful. It is an excellent tool for exploring hydrologic characteristics of a local system. It allows the consolidation of available data, allows future data collection priorities to be identified, and enhances the understanding of the hydrologic and environmental drivers of an aquifer system.
As good as a model may be it should not be allowed to replace responsible decision making. Instead, it should be used as a decision support tool. Decisions need to have a solid foundation, built on data and analysis, to be acceptable and defensible.
KOT Environmental Consulting Inc. (KOT-ECI) uses the USGS MODFLOW model. This model is widely used and with which we have extensive experience. MODFLOW has the capability of modeling all the geologic, hydraulic and hydrologic features that affect groundwater flow including recharge, and stream, wetland and lake interactions. We use the project stratigraphic model and historical water level data to build the preliminary model. Since the preliminary model is a dynamic water management tool, it is capable of receiving and analyzing additional data as it becomes available. The preliminary model identifies existing data gaps. We address these data gaps by designing and implementing a long-term project water-level monitoring program. Data from this program are continually used to enhance the accuracy and precision of the model.