Hydrology

Hydrologists evaluate the flow and chemistry of water. The movement of water through a wetland ecosystem regulates the supply of nutrients (or contaminants) to a wetland, controls the degree of saturation, and influences sediment transport through a wetland.

The principles of earth system science can be applied to wetlands to better understand their hydrology. Earth system science breaks down an area or problem into one or more reservoirs that exchange mass and energy. In hydrology, the reservoirs are the different places that water is stored (atmosphere, pool, soil, etc.), and this water will move from one reservoir to another. This exchange between reservoirs is called a flux and is expressed as an amount of exchange per time (i.e. (volume of water/time). By evaluating the different fluxes into and out of a wetland (the reservoir), a better understanding of what is important in controlling the hydrology and chemistry of a wetland can be developed. These reservoirs and fluxes can be combined into a simple mass-balance or water-balance equation that states all the fluxes into and out of the system (wetland) equal the change in storage in the wetland.

Ground-water flow is the focus of hydrologic monitoring in this project. To evaluate the ground-water flow, monitoring wells are installed. These wells are pipes equipped with a slotted screens at the end. The monitoring wells are used to measure ground-water levels (hydraulic head) and ground-water chemistry. The tops of all the monitoring wells were surveyed and the elevation of the water in the wells (hydraulic head) was determined by subtracting the depth to water inside the well from the well elevation. Ground-water flow directions can then be estimated because ground water flows from high hydraulic head to low hydraulic head. The rate of ground-water flow can be determined from the hydraulic gradient and the permeability (hydraulic conductivity) of the material the ground water flows through.