To combat severe streambank erosion threatening Davis Mill Road, Mercado Consultants designed and implemented 700 linear feet of stream restoration along Wildcat Branch. The stream’s proximity and steep embankment had caused a 10-foot headcut, leading to significant roadway instability. The solution centered on stabilizing the stream corridor while enhancing ecological function.
The restoration design incorporated a series of in-stream structures—including step pools, cross vanes, j-hooks, and rock sills—to dissipate energy, control grade, and redirect flows away from vulnerable banks. Tree that were removed were reused to establish aquatic habitat, and stream resiliency. In addition, imbricated riprap walls were installed at key points to control headcuts and further stabilize the channel.
The stream was realigned 50 feet away from the road and widened from 15 to 30 feet to accommodate flood flows. Mercado Consultants coordinated closely with M-NCPPC Montgomery Parks and during the design to ensure hydraulic performance and regulatory compliance. The project was fully designed, permitted, and constructed within 10 months. The effort earned the County Engineers Association of Maryland’s Midsize Project Award of Merit in 2021.
Following a 100-year flood event in 2019 that caused a catastrophic culvert failure and streambank collapse, Mercado Consultants led the two-phase restoration of a tributary to Cabin John Creek in the Carderock Springs neighborhood. Phase 2 of the effort—focused on long-term stream stabilization and water quality—featured an outfall retrofit that restored channel stability, improved aquatic habitat, and restored fish passage through the existing culvert.
The design consisted of a 100-foot long plunge pool constructed immediately downstream of the replaced culvert to dissipate high-energy flows and capture sediment. A downstream rock sill elevated water levels to enable upstream fish passage, while cascading littoral shelves were integrated along the pool’s banks to foster native riparian vegetation and reduce bank erosion. To further dissipate energy and mimic natural stream morphology, transition riffles, root wads, boulders, and cobbles were installed downstream, creating diverse flow conditions and aquatic habitat.
The project was carefully coordinated with M-NCPPC Parks and minimized impacts to mature trees and sensitive parkland areas. The project also required obtaining a FEMA Conditional Letter of Map Revision process for changes to the FIP mapping.
Mercado Consultants supported the Chesapeake Bay Crossing Study – Tier 2 NEPA by providing Natural Resource Identification (NRI) services for approximately 150 acres on Maryland’s Eastern Shore. The project, led by MDTA and FHWA, aims to evaluate new alignment alternatives for a third Bay crossing to address long-term congestion along the U.S. 50/301 corridor. Mercado Consultants staff delineated wetlands, Waters of the U.S., and other sensitive resources across potential roadway alignments leading to the proposed bridge approaches. Mercado Consultants also conducted field surveys and assessed environmental impacts associated with various build alternatives under consideration in the Tier 2 NEPA study. The findings contributed to the evaluation of ecological impacts and informed the development of avoidance and minimization strategies. Mercado Consultants also provided technical input to support the NEPA Tier 2 documentation process.
Following major flooding during Hurricane Ida in September 2021, Mercado Consultants was tasked by Montgomery County to investigate the cause of flood impacts across the Twinbrook and Rockcrest watersheds in Rockville, Maryland. The study focused on a 679-acre drainage area and was initiated to evaluate the performance of a 400-foot-long box culvert beneath Twinbrook Parkway. Mercado Consultants conducted extensive field investigations, topographic surveys, and lidar scanning to create a detailed hydrologic and hydraulic model. Over 500 storm drains and 5 miles of open stream channel were identified and incorporated into the hydraulic model, which was used to simulate both the Hurricane Ida rainfall and NOAA Atlas 14 design storms. Mercado Consultant’s model closely matched observed high-water marks within one inch, validating the approach and helping the County understand the hydraulic performance of the watershed.
Hit enter to search or click X to close