Effects of Inland Lake Water Level Fluctuations on Ecosystem Services Due to Predicted Seasonal Precipitation Shifts

Abstract

This research investigated potential changes to recreational and aesthetic ecosystem services in the BWCAW eco-region due to potential climate pattern changes over the next 100 years. The research looked at past literature regarding validation and definition of ecosystem service studies, the potential climate changes, and use of water level as an index to assess productivity in the littoral zone. This was accomplished by utilizing historical data available for a large boreal lake and simplified precipitation prediction techniques (two state Markov Chains and maximum likelihood gamma distributions) to create inputs to a model. The HEC-HMS modeled watershed produced outflows which were compared to a pre-prediction period state outflows to ascertain water level fluctuations, indicators of hydrologic alteration (IHA) and degree of impact to watershed ecosystem services. It became clear that despite a near inversion of base seasonal precipitation patterns and continued growth of total precipitation that snowpack and spring thaws controlled the lake water level response in the scenario researched and that overall behavior remained nearly consistent with little negative impact. The research indicates that if the scenario plays out, long term economic impact through recreation and aesthetic linked ecosystem services will remain stable. It is recommend that future research use more robust modeling software, spatially varying data sets and direct quantitative measurements of seasonal recreational use and value over several years.