Case Study: Rock Springs Farm
Written by: Rachel Washington and Chris Buttermore, PE
Located in southern St. Johns County, Rock Springs Farm offers single-family homes and amenities that include lakes, trails, clubhouse, pool, and public County-owned park.
MDG provided civil engineering services for the new 182-lot subdivision. Our team reviewed the current concept plan, developed by another firm, and coordinated with the project attorney to modify the PUD based on the new concept plan. MDG also prepared construction plans and obtained permits with the required regulatory agencies.
Key Facts About the Project
- Chris Buttermore, PE, was the project manager. Learn more about him here.
- Design included site layout, grading & drainage design, utility design, roadway design, and landscaping design.
The main challenge with this project was that a significant portion of the site was within a flood plain.
When developing in a flood plain, and raising the project site, there has to be compensation elsewhere for the displaced flood storage. This greatly impacted the site layout as a significant portion of the site would need to be dedicated to flood compensation.
St. Johns County and SJRWMD also required the applicant to determine any off-site flood impacts and ensure the development would not adversely affect off-site flooding (raise any flood levels).
MDG worked closely with an experienced flood consultant (Humphries Engineering), as well as SJRWMD and SJC to determine the requirements for this project. Our team adjusted the conceptual layout as needed to allow an area to be dedicated to a flood pond.
Jim Humphries and the MDG team worked together to determine the exact needs in reference to the sizing the flood pond, needed control structures, and drafting a model and report showing no adverse impacts within the site or downstream off the site.
All this took place while balancing an acceptable number of lots for the client and incorporating the County park. The flood pond was completely separate from the typical stormwater ponds which take on the rainwater for the site, and would only be for significant rainfall events.
The flood compensation of this magnitude that is required is not typical for our projects. The same can be said for the St. Johns County park that was designed and dedicated. There was also a large FDOT swale that went through the middle of the site which conveyed a lot of runoff from their US 1 system. The MDG team had to work around this ditch, with the exception of the one crossing (box culvert), to access the other half the site.
In conjunction with our Senior Planner, Shannon Acevedo, our team was able to design, permit, and modify the PUD (to remove a proposed boardwalk through wetlands) in just over a year. This helped to save on costs and avoid unnecessary wetland impacts.
Our team was responsible for ensuring all utility connections to the lots worked, as well as making sure the site would handle heavy rain events without flooding. This was accomplished with the flood pond and multiple stormwater ponds, structures, and pipes. All of the designs had to be approved by jurisdictional agencies to make sure we were in compliance with requirements and standards.
“Although there was several significant challenges associated with the project, we had the right team and experts in place to keep everything on track. The client was also very understanding and worked with us on the challenges.” – Chris Buttermore, PE, Project Manager
MDG has been contracted to provide professional services for almost 300 residential-focused projects. These projects range from individual residential projects to multifamily units to large-scale residential communities. Some of these residential communities have included, Riverside Cottages, Isles at Antigua, Villages of Valencia, Julington Creek Plantation, Stillwater, Deerfield Preserve, and Grand Reserve East.
In need of our land development services for your project? We would be happy to partner with you!