Creating a plan to ease stress on North Carolina’s watersheds

Coastal Watershed Management Services

North Carolina needed to develop a watershed-scale hydrologic model for two pilot watersheds as part of a larger assessment plan. Our goal? To create defensible and repeatable methodology to assess the functional health of coastal watersheds in the state. Our methodology is intended to be the basis for subsequent guidance that the N.C. Ecosystem Enhancement Program (NCEEP) can use to create consistency in coastal watershed planning efforts.

The major stressor in both watersheds has been from altered natural hydrology due to ditching, agricultural practices, and increased impervious surfaces. Based on our team’s knowledge and experience with soils, wetlands, geomorphology, and hydrology in the North Carolina Coastal Plan, we developed a natural conditions scenario for both study areas to allow for the simulation of hypothetical runoff volumes associated with conditions prior to human intervention.

In the end, we developed hydrologic modeling system (HEC-HMS) models for natural, current, and predicted conditions in the two study areas, estimating stream flow volume, velocity, and time to peak in the major tributaries of the watersheds. We also produced a technical memorandum describing modeling assumptions and input parameters to a repeatable level of detail. The result? North Carolina can now efficiently develop consistent guidelines for their coastal watersheds.