Sundance Apartments Helena, LLC presented to WWC the issue of the development of a 10-acre site outside of the City limits of Helena, MT with a 216-unit apartment complex. The site was constrained by access to the east, utility easements running through the property, the desire of high-density development, and lack of area for stormwater detention and treatment. WWC met with the client and the City of Helena jointly to determine the permitting process for annexation, zoning, and site design in order to complete the project on the client’s timeframe and budget. The most unique aspect of the project was the lack of space for typical stormwater detention ponds to treat stormwater onsite. This required the use of underground stormwater detention areas with pre-treatment structures under the driving and parking areas in order to allow for high-density development. This was the first project utilizing a large underground stormwater detention approved by the City of Helena. The result was successful annexation and zoning of the property in order to develop the project utilizing City of Helena water and sewer services and an innovative stormwater detention and treatment system.