Thomas & Hutton provided run-off modeling, surveying, civil engineering, irrigation system design, study, preparation of construction plans, permitting, cost estimating, and bid support to the Town of Bluffton, a coastal community with strong ties to its local water body, the May River. The aesthetics and views of the May River increase the popularity of the areas for residential, commercial, and tourist visitation growth, tying the Town’s economic conditions directly and indirectly to the river. Since its first annexation in 1987, the Town has grown from one square mile in area to approximately 54 square miles in size. Throughout its rapid growth, the Town has actively sought to protect the May River and all of its natural water resources through a variety of means, including adopting a volume-based stormwater management ordinance in 2010.
Pine Ridge, a single-family residential community, was developed prior to the 2010 volume-based stormwater ordinance. While the development meets the peak rate requirements, it does not meet the volumetric requirements of the current ordinance. Numerous projects permitted under the current volume-based ordinance have used irrigation systems with reused stormwater from an on-site lagoon as the supply to achieve stormwater run-off volume compliance. Pine Ridge involved the design and permitting of an irrigation system for existing open spaces using the lagoon network of Pine Ridge as the water supply. Drawing down the lagoon’s water surface from the design outlet control elevation will create storage capacity so that future smaller rain events will be retaining entirely on-site. This will result in a volumetric reduction in stormwater run-off leaving the property, when compared to its current conditions. The retrofitted lagoon networks were designed to bring the development into compliance with the current volumetric requirements of the Town’s stormwater ordinance. The Town also intends to monitor the Pine Ridge project and will assess the effectiveness of this type of run-off volume control. This is the first large-scale demonstration project in Bluffton showing the benefits of modifying an existing BMP to improve both water quality and quantity outputs from an established development.