A Bayesian SPARROW modeling framework to support adaptive management in Georgian Bay watershed

Session: 35. - Watershed Modeling across all Scales from Small to Large

Alex Neumann, University of Toronto Scarborough, [email protected]
Dong-Kyun Kim, University of Toronto Scarborough, [email protected]
Agnes Richards, Environment Canada, [email protected]
Yuko Shimoda, University of Toronto Scarborough, [email protected]
George Arhonditsis, University of Toronto Scarborough, [email protected]

Abstract

The north-eastern embayments of Georgian Bay receive nutrient loads from Precambrian Shield watersheds including Muskoka Lakes. We applied the SPARROW watershed model to estimate baseline annual average phosphorus (P) yields across the entire north-eastern Georgian Bay watershed. The model has been calibrated against a combined dataset of stream samples of tributary P from provincial, municipal, citizen science, conservation authorities and university research monitoring programs. We quantified nutrient yields from gauged and ungauged sub-watersheds, and delineated “hot spots where excessive nutrient export can occur. A unique feature of the project is the application of a Bayesian formulation with a Conditional Autoregressive component to account for spatial variability of P yields, which could not be addressed otherwise due to limited information about P mobilization from the Precambrian Shield. P yields from forested, agricultural, urban areas and septic tanks have been compared against similar estimates from the Lakeshore Capacity Model and P Loading Tools in Lake Simcoe and Nottawasaga watersheds. Our study has corroborated the previously reported positive relationship between P export from boreal forests and the relative contribution of peatland areas. We also identified twofold increase in P yields from farming activities in the North compared to farms in Southern Ontario.

1. Keyword
watersheds

2. Keyword
wetlands

3. Keyword
Georgian Bay

4. Additional Keyword
SPARROW