Rock Island District Public Notices

Bowman Property, LLC (CEMVR-RD-2022-0252)

Rock Island District
Published Aug. 17, 2022
Expiration date: 9/7/2022

A. The applicant proposes to construct a new 109-acre mixed use residential and commercial development, Forevergreen Estates, in North Liberty. The development concept is to provide medium to high density housing ranging from 36-plexes to duplexes in additional to commercial space, to provide a minimum of 640 dwelling units across the development. The applicants stated purpose and need for the project is to provide stormwater quality and quantity treatment for the upland residential and commercial developments. The majority, 94 percent of the stormwater basin is necessary to meet the upland residential development and 6 percent of the basin will be utilized to meet a proposed commercial development. To meet stormwater requirements, a wet bottom detention basin was designed to provide 24-hour detention of the 1-year, 24-hour event for the project area. The applicant has stated that as a result of the sizing calculations and to comply with stormwater management standards, it was determined that a 5.5-acre basin with 1.3-million cubic feet of storage was required. The project will permanently impact 1.74 acres of emergent wetland for the construction of a dam and for the basin itself. The applicant has proposed to purchase 1.74 acres of wetland mitigation credits.

B. The applicants stated avoidance and minimization efforts were evaluated to try and reduce wetland impacts such that the project would qualify for a nationwide permit. The applicant performed an alternatives analysis based on the project purpose to provide for a stormwater basin for the proposed developments. Based on conversations with the Corps the geographic scope are those areas contiguous with the project site and configuration within the existing parcels where the developments are proposed. The alternatives analysis was based on availability, acquisition cost, logical constraints, construction costs, dwelling unit reduction, cost of dwelling unit reduction, and environmental impacts based on the presences of waters of the U.S., topographic information, soil surveys, flood maps, and a wetland delineation. In addition, an assessment of wetland functions was also utilized to provide an analysis of the hydrologic, water quality, and ecological functions of the identified wetland areas. Two off-site parcels, and on-site configuration within the existing parcels were reviewed and a comparison matrix was provided. A copy of this analysis can be provided upon request.

C. Regional General Permit (RP) 48 for residential developments within the State of Iowa is currently on public notice until August 6, 2022. This RP allows for the construction of residential developments, including attendant features such as storm water management facilities, impacting up to 2 acres of waters of the U.S. As this project meets the requirements for RP 48 (a majority of the stormwater basin is for residential developments), an RP will be issued if it becomes available prior to issuance of a standard individual permit for this project.