City of Boiling Spring Lakes EWP DSR
Boiling Spring Lakes, North Carolina
During June 2019 LDSI assisted Resource Institute, Natural Resource Conservation Service, NCDOT, and other federal and state agencies (FEMA, CAMA, USACE, DWR, DEQ, NCDA&CS, etc.) with disaster site investigations. LDSI generated a preliminary planning-level survey to estimate the repairs required to restore the various Boiling Spring Lakes sites to pre-hurricane condition. The failure was first noticed following Hurricane Florence, which produced 29.5 inches of rainfall over the 4-day event within the Boiling Spring Lakes – Wilmington area.
LDSI was asked to assist with the Disaster Survey Report, perform a site visit, perform a preliminary feasibility survey, develop a feasibility design, and develop an opinion of probable cost. LDSI prepared maps detailing the proposed repair efforts including streambank stabilization and slope grading, debris and sediment removal from the channel, instream structure installation, and re-vegetation of the channel banks as well as other disturbed areas.
LDSI developed the following concepts within the feasibility design:
- Re-grading to establish the shorelines and stabilize the slopes.
- Re-grading streambanks to establish the natural pattern and profile, following the storm.
- Removal of accumulated sediment within stream channels to prevent excess sediment from accumulating in downstream culverts.
- Repair of stormwater infrastructure that is leading to scour and undermining of transportation infrastructure.
- Repair dam/levee to attenuate stormwater which existed prior to Hurricane Florence.
- Establish a hardened spillway to serve as an auxiliary spillway for other large rainfall events.
- Re-vegetation of the berm and disturbed areas to minimize erosion post repair.
LDSI completed the documents as required by the federal agencies to move the project from the planning level to the approve-appropriated level. The engineering services for this project were approximately $12,120 for DSR assistance. The estimated construction repair cost at the completion of the concept plans was approximately $1.2 million.
- May 2019 – July 2019
- Disaster Response
- Government Program Compliance
- Watershed Analysis
- Drainage System Design