Royall Avenue Basin Drainage Improvement Project

Description

The Town has contracted with Thomas and Hutton engineering consultants to design an upgraded drainage system for the Royall Avenue Basin. Bids were received and Lowcountry Sitework was selected as the construction contractor. The project construction phase started on October 1, 2021.

The upgraded system will provide a ten-year storm level of service. The Town currently uses a ten-year storm event as the design standard for new stormwater systems. A ten-year storm event has a ten percent chance of being equaled or exceeded within a one-year period. Thomas and Hutton used the ten-year storm as the benchmark for the level of service even though the existing system was installed well before a design standard was adopted. Though there may still be areas of standing water in larger rain events, water will recede more quickly with the new system in place. Also, areas that previously relied solely on infiltration will now be connected to the new drainage system. Our goal is to limit flooding impacts on structures. Ponding in yards is anticipated during more intense storms. 

The original drainage system incorporated shallow roadside swales. Over time, many of these swales have filled in. In many cases, homeowners added street parking in these areas. As part of this project, many of the swales will be restored within the right-of-way. Homeowners should maintain these areas to help their lots drain and also to help their upstream neighbors’ lots drain. 

The construction will include installing new pipes, upsizing old pipes, and re-establishment of swales. As part of this process, some trees within the right-of-way and drainage easements will have to be removed. Check out the interactive map of the project area below:

Status (As of December 3rd, 2021)

  • Design and permitting complete
  • Signed contract with the contractor
  • Project staking
  • Silt fence installation 

Schedule

  • Construction phase started October 1st, 2021

What to expect:

  • Some trees will need to be removed. You can see the trees that are currently planned to be removed on the interactive web map above. Town ordinances for tree removal will be followed. The Town has contributed funds to the Tree Bank in accordance with the Tree Mitigation calculations. In addition, the Town may plant trees if opportunities arise during and after the project at the discretion of project leaders to prevent conflicts with newly installed infrastructure. 
  • Traffic will be impacted. There will be crews and construction equipment along the work areas. We will try our best to update the location of the crews in a timely manner. The interactive web map above shows where worksites will be located in real-time. 
  • On-street parking will be removed and will not be replaced. 
  • Driveway aprons removed will be replaced with basic concrete or asphalt aprons. Special finishes or decorative materials will not be used.
  • If construction is required on an easement located on your property, it may be necessary to remove landscaping or structures within the easement. These items will be removed and will not be replaced. The Town will only replace sod. Easements are shown on plats recorded with the County’s Register of Deeds. To see if there is an easement on your property click here. And for a helpful video on how to look up your property plat, watch this video. 
  • Expect noise with the construction. The Town’s noise ordinance will be adhered to which allows work between 7 AM to 9 PM. However, please note that there may be special conditions that require work outside these hours. 
  • A majority of the work will be conducted within the road right-of-way. In general, the right-of-way along a street extends approximately 10 feet into what people traditionally consider “their yard.” Landscaping, hardscaping, irrigation, dog fences, etc. within the right-of-way will be removed and not replaced. Sod will be restored. 
  • Rights-of-way and easements will be staked by a professional land surveyor prior to any construction. 
  • Prior to construction, you may see small flags or spray paint along the rights-of-way. This indicates that there is an underground utility in this area. Our contractor is required to have utility locates prior to any excavation. 
  • There may be brief periods of water outages. There are several locations where water and sewer utilities need to be relocated to make room for new or upsized pipes. The Town will work closely with Mount Pleasant Waterworks to ensure that residents receive adequate notifications of any outages.  
  • Once the project starts, weekly updates will be provided on this webpage.
  • For safety purposes, we request that residents refrain from entering active work areas. 
  • The Town will continue to take precautions regarding COVID-19. Please be mindful of this when approaching our staff or contractors.
  • Project signs will be going up the week of (Sept 20th).


Cost

Project Bid Amount: $9,686,211.92

Resources

View the Old Village Watershed Study

Contact

Please submit questions, comments, and concerns through our contact form or call (843) 849-2022.