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Stormwater Management Division

Mark S. Richmond, Chief

6751 Columbia Gateway Drive, Suite 514

Columbia, MD 21046



Little Patuxent and Middle Patuxent Watershed Assessment

The Howard County Department of Public Works is undertaking a comprehensive watershed assessment within the Middle Patuxent River and the Little Patuxent River watersheds. The watershed assessment is being performed to create an inventory of the natural resources as well as existing problems (erosion, trash, lack of wooded stream buffers, etc.) within these watersheds. Another result of the assessment will be a list of potential projects that can be done to protect and restore these resources, address the problems, and ultimately improve water quality in our County streams and water bodies.

This assessment will measure current environmental conditions and identify opportunities for restoration projects to be included in the capital budget.  These projects will improve water quality in the County’s streams and rivers as well as the Chesapeake Bay.   Potential projects being investigated include stream restoration, adding water quality treatment to existing stormwater management ponds, constructing new stormwater management facilities, performing reforestation, and stabilizing existing storm drain pipe outfalls.

Due to the large overall study area, the field work is being conducted in four distinct areas -- Northern Little Patuxent, Southern Little Patuxent, Northern Middle Patuxent, and Southern Middle Patuxent watersheds. The County welcomes public participation in the development of the watershed study. The County will conduct a public meeting in each of the four study areas to report on the findings of field work results, to describe the next steps in the assessment study, to review possible restoration techniques, and to discuss the status of its countywide plan for meeting Chesapeake Bay Total Maximum Daily Load (TMDL) goals. Crews of two or three County employees or consultants have conducted the field assessments, which will entail performing visual observations, taking photos, preparing sketches, and entering the data into handheld field tablets. 


For the purpose of this study the two large watersheds have been divided into smaller study areas. The Little Patuxent watershed has been divided into the Northern and Southern Little Patuxent areas and the Middle Patuxent watershed has been divided into the Northern and Southern Middle Patuxent areas as depicted on the map below 
Little and Middle Patuxent Watershed Map  

Now that the field assessments have been completed, concept designs are being developed for the highest ranked sites. A draft and then final report will be produced once the field assessments and concept plans for restoration have been completed. Public meetings have been scheduled in December 2015 to present the results from the field assessment, to solicit public input, and to discuss proposed restoration projects being suggested by the study.

If you have any specific questions or concerns or would like additional information regarding the watershed assessment, please contact the County by emailing khargadin@howardcountymd.gov or calling 410-313-6444.

Public Meeting Update - September 18, 2015The second round of public meetings have been established and are as follows:

Wednesday December 2, 2015 Northern Middle Patuxent Watershed - Gary J. Authur Community Center
2400 Route 97, Cooksville, MD  21723

Thursday December 3, 2015 Southern Little Patuxent Watershed - North Laurel Community Center
9411 Whisky Bottom Road, Laurel, MD 20723

Wednesday December 9, 2015 Southern Middle Patuxent Watershed - Robinson Nature Center
6692 Cedar Lane, Columbia, MD 21044

Thursday December 10, 2015 Northern Little Patuxent Watershed - Howard Community College
10901 Little Patuxent Parkway, Columbia, MD 21044

All meetings will be from 6:30 pm - 8:00 pm.

Past meeting presentations:

June 17, 2015 -  Southerm Middle Patuxent Watershed  

June 22, 2015 -  Northern Little Patuxent Watershed  

June 24, 2015 -  Southern Little Patuxent Watershed  

June 30, 2015 -  Northern Middle Patuxent Watershed   



Downtown Ellicott City Flood Study

A detailed floodplain analysis using both one-dimensional and two-dimensional hydraulic modeling is available for viewing. The floodplain study considered several standard rainfall events as well as the rainfall event that resulted from the remnants of Tropical Storm Lee on September 7, 2011. The study also included a conceptual assessment of potential flood mitigation options.

  • Floodplain Study Report  
  • Inflow Hydrograph Comparison 
  • Rainfall Intensity Distribution Comparison 
  • Cumulative Rainfall Distribution Comparison 
  • Flooding Depth and Limits – Multiple Storm Events  
  • Conceptual Mitigation Options 

    The Howard County Flood Mitigation Plan 2013 Progress report is available for viewing here.


    The Tiber-Hudson and Plumtree Branch Stream Corridor Assessment

    a visual survey of the stream corridor to document conditions that potentially affect flood conditions, is now available. Also see the supplemental Case Study: Valley Mede-Ellicott City Tropical Storm Lee Flood Event 


    Howard County and the Master Gardeners:

    are providing free rainbarrels to residents who attend their training workshops. Here is a workshop schedule.  

    Learn more about the Watershed Protection and Restoration Fund

    MS4 NPDES Permit Annual Update Number 19

    In accordance with Howard County’s Municipal Separate Storm Sewer System (MS4) National Pollutant Discharge Elimination System (NPDES) Permit (Number MD0068322, 00-DP-3318), the County must prepare Annual Updates to report on the progress made during the preceding permit year. Progress is reported on compliance with pollutant source identification in stormwater runoff; water quality impacts; discharge characterization; management programs; watershed assessment and planning; watershed restoration; assessment of controls; program funding; Total Maximum Daily Loads (TMDLs); and special programmatic conditions. The County submitted the Annual Update for its 19th permit year to the Maryland Department of the Environment (MDE) on September 15, 2014. To view the County’s Annual Update Number 19 and the supporting databases, click here. 


    Mission Statement

    The mission of the Stormwater Management (SWM) division is to advance the quality of life for the citizens of Howard County through the improvement and management of the quality and quantity of water that originates in, falls onto, or passes through the county on its way to the Chesapeake Bay.

    The SWM division will accomplish this by:

    • communicating to the public the value of clean water and the ways they can personally improve water quality, 
    • monitoring and maintaining our public and private storm water facilities, 
    • planning, implementing, and maintaining a program for good water resource management, 
    • partnering with individuals, citizen volunteers, local environmental groups, businesses, schools, and other government agencies in an effort to promote beneficial water quality management,
    • responding to public inquiries and complaints in a courteous and timely manner, and 
    • evaluating and implementing technologies consistent with stormwater best management practices (BMP's). 


    Howard County Code


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