Date of Award

Winter 11-20-2019

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Civil Engineering

Advisor

Aria AMirbahman

Second Committee Member

Stephen Norton

Third Committee Member

Raoul Marie-Couture

Abstract

Lake Auburn, Maine, USA, is a historically unproductive lake that has experienced multiple algal blooms since 2011. The lake is the water supply source for a population of ~60,000. We modeled past temperature, and concentrations of dissolved oxygen (DO) and phosphorus (P) in Lake Auburn by considering the watershed and internal contributions of P as well as atmospheric factors, and predicted the change in lake water quality in response to future climate and land-use changes. A stream hydrology and P-loading model (SimplyP) was used to generate input from two major tributaries into a lake model (MyLake) to simulate physical mixing, chemical dynamics, and sediment geochemistry in Lake Auburn from 2013 to 2017. Simulations of future lake water quality were conducted using meteorological boundary conditions derived from recent historical data and climate model projections for high greenhouse-gas emission cases. The effect of future land development on lake water quality for the 2046 to 2055 time period under different land-use and climate change scenarios were also simulated. Our results indicate that lake P enrichment is more responsive to extreme storm events than increasing air temperatures, mean precipitation, or windstorms; loss of fish habitat is driven by windstorms, and to a lesser extent an increasing water temperature; and watershed development further leads to water quality decline. All simulations also show that the lake is susceptible to both internal and external P loadings. Simulation of temperature, DO, and P proved to be an effective means for predicting the loss of water quality under changing land-use and climate scenarios.

Download

Share