Maryland State Highway Administration – Environmental Programs Division
- Stream Assessment and Restoration Design
- Environmental Permitting
- Water Quality Improvements
- Natural Resources Inventory/Wetland Delineation
- GIS Analysis
- Aquatic and Riparian Habitat Analysis
Coastal Resources, Inc. (CRI) provided design services for the Maryland State Highway Administration’s (SHA) Intercounty Connector (ICC) Environmental Stewardship (ES) stream restoration site PB-119. CRI provided geomorphic assessments, hydrologic and hydraulic analyses, stream restoration design services, natural resource inventories, wetland delineations, forest stand delineations, environmental permitting, and will provide designated specialist/inspection services during construction.
PB-119 is a first order urban stream located within the Good Hope subwatershed of the Upper Paint Branch watershed. The study area included approximately 1,000 feet of the Left Branch of the Good Hope. Urban development resulted in channel incision, bank erosion, irregular plan form geometry, and significant in-stream sedimentation that impacts water quality within the reach, and the downstream urban coldwater fishery of wild brown trout. At the request of SHA, CRI completed a detailed aquatic habitat assessment of PB-119 prior to commencing design activities. The results of this assessment highlighted significant habitat deficiencies within the project reaches. It was generally documented that a lack of overhead cover and excessive sedimentation impaired pool quality, while the riffles were found to be embedded, very wide and shallow, and also lacked overhead cover. As stabilization of upstream tributaries and construction of upstream stormwater facilities are part of the ICC ES package, significant water quality improvements are anticipated. With this in mind, an improvement in aquatic habitat within the PB-119 project reaches could be highly beneficial to the macroinvertebrate population. With both construction feasibility and natural resource impacts in the mind, SHA and CRI developed the following goals: reduce channel incision, reduce in-stream sedimentation, enhance benthic macroinvertebrate and fish habitat, and improve/enhance the riparian buffer. CRI conducted hydraulic analyses and geomorphic assessments to evaluate the current geomorphic condition of the stream and to compare to geomorphic data from previous assessments. Geomorphic measurements such as cross sections, profiles, and pebble counts were completed in the same locations as the previous assessment, and compared to determine the magnitude of instabilities within the reach. Historic maps and photographs were reviewed to evaluate land use changes within the watershed, and stream channel plan form changes over time. Two site specific stream treatments were developed for PB-119 to meet the project goals of enhancing aquatic habitat and stabilizing the stream. A Riffle Bench was designed to narrow existing riffles and increase low flow velocities to decrease embeddedness and sedimentation, and a Large Woody Debris structure was designed to stabilize the outside meanders of pools and provide aquatic habitat through both dead and live trees. Wetlands on the PB-119 floodplain were also delineated and riparian vegetation density and composition was observed. Areas in need of restoration/stabilization were identified, and remedial designs developed.
CRI prepared the Joint Permit Application, Final (90% design), and PS&E (100% design) submittals, and erosion and sediment control plans. CRI also presented the design strategy to review agencies at Interagency Workgroup (IAWG) and Brown Trout Advisory Workgroup (BTAWG) meetings and acquired all environmental permits, and erosion and sediment control permits. Final Design Plans, Specifications, and Estimate for the restoration of the PB-119 site were completed in 2012. CRI will also provide Designated Specialist services during construction.