Watershed Surveys

Watershed Surveys look at the impact that human and natural activities have on the watershed. Watersheds are areas of land that catch rain or snow and then drain into bodies of water such as marshes, wetlands, rivers, streams, lakes, or to underground sources. Howard County lies within the watersheds of the Patapsco and the Patuxent Rivers, which flow toward the Chesapeake Bay. The Patuxent River drains three quarters of the county, while the Patapsco drains the remaining one quarter. To better assess the conditions in the County's streams, the Stormwater Management Division is collecting information on the physical, biological, and chemical conditions of the county's watersheds.

Stream Corridor Assessment

A physical assessment provides information on erosion sites, fish blockages, channelized stream sections, in- or near-stream construction, inadequate stream buffers, exposed or discharging pipes, trash dumping sites, and unusual conditions found in a stream. Information is collected in order to determine the severity of each problem. The Stormwater Management Division, with the assistance of the Department of Natural Resources (DNR) and the Maryland Conservation Corps, has performed Stream Corridor Assessment Surveys in following watersheds:

The Main Patuxent Watershed is located in the western portion of Howard County. This watershed is particularly important because water flowing over this area of land contributes drinking water to the Rocky Gorge and Brighton Dam reservoirs. It is very important that residents in this watershed keep pollutants such as fertilizers and pesticides from entering the water supply.

The Little Patuxent Watershed is located in the central eastern portion of Howard County. The Little Patuxent watershed is currently the most impacted watershed in Howard County due to its high population density. Howard County is currently working on developing strategies that are designed to remediate erosion and lack of tree buffers; the two largest problems within this watershed.

Little Patuxent Stream Corridor Assessment


The Middle Patuxent Watershed is located in the central portion of Howard County. It is the only watershed whose boundaries are completely located within the County.

Middle Patuxent Stream Corridor Assessment

The Patapsco Watershed is located in the northern portion of Howard County. A watershed restoration plan is currently being designed for this watershed.

Patapsco Stream Corridor Assessment

In addition, a more detailed stream corridor assessment was conducted in 2005 in the Patapsco and Deep Run subwatersheds for the Patapsco WRAS.

Deep Run and Patapsco River Stream Corridor Survey

Biological Monitoring Survey

In addition to the physical stream survey, the Stormwater Management Division conducts biological assessments of the streams in Howard County's watersheds. The biological assessment will study the benthic macro invertebrates (bottom dwelling organisms) that live in our streams. Bottom dwelling organisms are a good indicator of water quality and can be used to determine stream health. The surveys use methods similar to those used by the Department of Natural Resources (DNR) in their Maryland Biological Stream Survey (MBSS).

First Round

Little Patuxent, Upper and Lower Brighton Dam, and Cattail Creek Watersheds
Little Patuxent, Upper and Lower Brighton Dam, and Cattail Creek Watersheds

Middle Patuxent Watershed
Middle Patuxent Watershed

Rocky Gorge, Hammond Branch, and Dorsey Run Watersheds
Rocky Gorge, Hammond Branch, and Dorsey Run Watersheds

Patapsco Watersheds
Patapsco Watersheds and Appendices

Second Round

Cattail Creek and Brighton Dam
2005 Cattail Creek and Brighton Dam

Little Patuxent Watershed