Stormwater Management Guidelines
The Planning Department and the National Roads Authority have been working together to draft revised procedures for addressing stormwater management on Grand Cayman. These policies are available for public review, as well as an online form to assist applicants with determining their stormwater infrastructure requirements. Questions or comments can be directed to [email protected] Please click here.
Guidelines for Stormwater Management Plan Preparation
Developments are encouraged to implement state-of-the-art techniques that manage stormwater runoff through redesigned streets, open spaces that take into account the natural drainage characteristics, and overall designs which require less corrective measures in the long term. When a site is developed, the design should maintain drainage characteristics of the site as much as is feasible through innovative design and use of alternative construction techniques. Development sites should be designed so that post-development stormwater runoff is less than pre-development runoff.
For major developments, applicants shall demonstrate that the Stormwater Management system can be designed to include storm water runoff produced from a rainfall intensity of 2 inches per hour for one hour of duration and ensure that surrounding properties that are lower and nearby public roadways are not subject to stormwater runoff from this site.
In preparing a Stormwater Management plan, the following is required
>> Applicant information such as Name, legal address, and telephone number, common address and legal description of site as well as contact name of designer of the SWM Plan
>> Mapping of proposed development site and surrounding area (recommended scale of 1" = 50.) which illustrate at a minimum:
>> Hydrologic and hydraulic analysis including:
Preliminary landscaping plans for stormwater treatment practices and any site reforestation or re-vegetation.
For smaller developments, should the applicant elect to address site’s drainage conveyance system by vertical wells, a minimum of 1 well per every 4,500 square feet of impervious surface area shall be provided, which is the combined square footage for sidewalks, parking and roof areas. Stormwater drains shall be located in the parking lot and soft landscaped areas with parking areas sloped towards the drains. The minimum specifications of the wells hall be one hundred (100) feet deep and eight (8) inches in width.
Prepared by the Transportation Planning Unit
National Roads Authority
Revised June 2006