|RENKENBERGER, JAISON - University Of Maryland|
|MONTAS, H.J. - University Of Maryland|
|LEISNHAM, PAUL - University Of Maryland|
|CHANSE, VICTORIA - University Of Maryland|
|SHIRMOHAMMADI, A. - University Of Maryland|
|BRUBAKER, KAYE - University Of Maryland|
|ROCKLER, AMANDA - University Of Maryland|
|HUTSON, THOMAS - University Of Maryland|
|LANSING, DAVID - University Of Maryland|
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2017
Publication Date: 3/23/2017
Citation: Renkenberger, J., Montas, H., Leisnham, P., Chanse, V., Shirmohammadi, A., Sadeghi, A.M., Brubaker, K., Rockler, A., Hutson, T., Lansing, D. 2017. Effectiveness of best management practices (BMPs) with changing climate in a Maryland watershed. Transactions of the ASABE. 60(3):769-782. https://doi.org/10.13031/trans.11.
Interpretive Summary: This study investigated the potential impacts of climate change on best management practices (BMP) effectiveness in an agricultural watershed located within the Chesapeake Bay basin of the US Northeast climate region. The region is expected to undergo the largest increases in annual rainfall and storm intensity as a result of climate change. BMPs were designed for the watershed’s critical source areas (CSAs), with the efficiencies needed to attain the target total maximum daily loads (TMDLs) under current climate and under climate change. These BMPs were then tested against all climate scenarios, using SWAT, to evaluate their robustness. Results of this study indicate that, in agricultural areas of the US Northeast climate region, where the Chesapeake Bay watershed is located, BMPs designed to reach the Bay TMDLs under current climate conditions will become insufficient with climate change. Furthermore, it is anticipated from this study that new BMPs will need to be implemented in large portions of agricultural watersheds in the US Northeast that are not currently identified as hotspots, just to uphold the water quality improvements resulting from current BMPs.
Technical Abstract: The potential impacts of climate change on BMP effectiveness were investigated using SWAT simulations for an agricultural watershed that drains into the Chesapeake Bay, in the US Northeast climate region. Critical Source Areas (CSAs) for sediments, nitrogen and phosphorus, identified for current and future climate (SRES A1B and A2), were classified by density to support BMP prioritization schemes. BMPs were designed for these CSAs and tested against current and future climate using SWAT simulations, to evaluate their robustness. A second set of BMPs was designed by optimization for all agricultural and urban lands in the study watershed, and was tested similarly for robustness. In both cases, the design goal was for the watershed’s water quality response to meet the Bay TMDLs once BMPs were implemented. Results indicated that density 2 and 3 CSAs (hotspots exporting excess amounts of 2 or 3 constituents) may be good prioritization targets but reaching the Bay TMDLs would still require targeting all CSAs. BMPs designed for CSAs under current climate were effective to reach Bay TMDLs under current climate but not under scenarios A1B and A2. BMPs designed for CSAs under future scenario A2 were effective to reach the Bay TMDLs under all climates, except for nitrogen under A2. Similarly, BMPs optimized for agricultural and urban lands, when designed for current climate, were effective in meeting the TMDLs for current climate only. Optimizing these BMPs for future climate produced a design that met TMDLs under both current and future climates, except for nitrogen with future climate. However, in this case, the nitrogen TMDL was exceeded by a smaller amount than in the CSA design. It was concluded that, in the US Northeast, BMPs designed to remediate water quality problems under current climate will be insufficient to maintain water quality with climate change. Increased annual rainfall and storm intensity will cause the proportion of watershed area needing BMPs to increase and current hotspots will generate excess amounts of new constituents that will require re-design of existing BMPs. Community-based participatory strategies will likely be required to foster BMP adoption and sustain water quality gains in the Chesapeake Bay region.