Moving Towards Sustainable Land Management in the Chesapeake Bay Through
Novel Engagement Strategies
Abstract
Each state and district within the Chesapeake Bay watershed has
cooperated with the Chesapeake Bay Program (CBP) to develop local
Watershed Implementation Plans (WIPs) that identify the type and
quantity of best management practices (BMPs) that, if implemented, are
estimated to meet 2025 Total Maximum Daily Load (TMDL) goals for Bay
water quality. However, top-down management of large regions, such as
the 167,000-km2 Bay catchment, is often necessarily limited by the
feasibility of providing implementation plans that are customized by
watershed hydro-physiographic characteristics and socio-political
considerations. The Bay simulation model divides the catchment into
watersheds of approximately 350 km2 each; these watersheds become the
Bay model’s smallest overland management unit. We used Bay WIP plans,
local information, and a hydrologic model called Topo-SWAT to model
three of these smallest-unit watersheds in more local detail. Our
smallest management unit became contiguous, similarly managed, cropland
areas (i.e., one or several neighboring agricultural fields) and these
management units were further divided by the topographic wetness index.
Our watersheds represent three distinct hydrological and geochemical
regions within the Chesapeake Bay catchment, namely Appalachian Valley
and Ridge – karst, Appalachian Valley and Ridge – nonkarst, and
Appalachian Piedmont. We modeled three scenarios for each watershed:
baseline (pre-WIP), WIP implementation, and “smarter” WIP placement
where we targeted BMP placements for cost-effectiveness. We then
compared results among scenarios as well as across watersheds. We are
interested to see how well the models agree at the watershed outlet,
discover cost-effective BMP placements within each watershed that meet
WIP goals, and compare our findings across the physiographic regions to
determine how they can guide regional planning.