Herring Bay, Middle Patuxent, and Lower Patuxent Watershed Assessment

Coastal Resources, Inc. (CRI) assisted the prime engineering consultant on this contract in performing watershed assessments for the Herring Bay, Middle Patuxent, and Lower Patuxent watersheds in Anne Arundel County, Maryland. The primary goal of this project was to assist the County in meeting assessment, restoration, implementation, preservation, and rehabilitation goals in accordance with National Pollution Discharge Elimination System (NPDES) permit conditions. For this contract, CRI assisted in the verification and modification of the County’s planimetric stream layer, the separation of streams into distinct reaches, rapid geomorphic and habitat assessments on each stream reach, environmental inventories on stream reaches, and processing of the final GIS data and stream database.

Watershed Assessment data were collected during the fall and winter of 2016-2017. Assessments were performed for all stream sections with landowner permission within the Herring Bay, Middle Patuxent, and Lower Patuxent watersheds. Stream sections were walked, using the County’s planimetric stream layer as a guide. Updates to the stream layer were made in the field using ArcCollector software and a Bluetooth capable GPS unit. Updates included adding or deleting stream reaches or adjusting the location of a mapped stream. Distinct reaches were identified based on changes in geomorphology and/or aquatic habitat. For all perennial stream reaches longer than 75 meters, a physical habitat assessment was performed following Maryland Biological Stream Survey (MBSS) protocols. A rapid geomorphic assessment was conducted for all perennial reaches and intermittent/ephemeral reaches longer than 75 meters. This assessment included a rapid Rosgen Level I classification and the calculation of Manning’s n. Inventory points were collected using ArcCollector for erosion, unmapped confluences, buffer impairments, dumpsites, utilities, stream crossings, headcuts, obstructions, ditches, and pipes. Data on habitat, geomorphology, and environmental inventory points were collected using a rugged field laptop and stored in a database. CRI also assisted with processing of the final GIS database, including rigorous QA/QC, stream flow designations, and reach break additions. CRI also assisted with 20 stream crossing surveys based on crossings identified by the watershed assessment fieldwork.


Anne Arundel County, MD


Anne Arundel County DPW Watershed Protection and Restoration Program

Key Services:

  • Habitat and Rapid Geomorphic Assessments
  • Stream Infrastructure and Environmental Inventory
  • Stream Crossing Surveys
  • GIS Data Processing