Seviulating the hydrogeologic setting of peatlands in the Kenai Peninsula Lowlands, Alaska

Ground-water flow simulations were constructed to evaluate the interaction between ground water and wetlands systems, focusing on peatlands in the Kenai Peninsula Lowlands, south-central Alaska. Peatland systems occur in both recharge and discharge zones along transects simulated in computer models, whereas toe slope wetlands occurred in discharge zones. Sensitivity analysis indicates that hydraulic conductance of subsurface units has a strong influence on the rates and directions of ground-water flow exchanged between peatland systems and the surrounding mineral sediments, and needs to be further characterized to assess the hydrologic function of wetlands in the Kenai Lowlands. Perching of the water table was simulated in several modeling scenarios, altering ground-water flux rates to wetlands and shifting recharge zones to topographically lower areas. Runoff (saturated surface flow and shallow interflow) was the dominant flux in all simulations. Our exploratory simulations suggest three avenues for future research using computer modeling to evaluate wetland hydrologic function in the Kenai Peninsula: 1) improved simulation methods to better characterize ground-water perching and overland flow, 2) better characterization of the distribution and hydrogeologic parameters of geologic units, and 3) collection of hydraulic head data in and near representative wetland systems to calibrate computer simulations.