Paseo de las Iglesias Ecosystem Restoration Feasibility Study

Overview

The Paseo de las Iglesias Environmental Restoration Feasibility Study was undertaken by the US Army Corps of Engineers and the Pima County Regional Flood Control District, with input from the City of Tucson and other stakeholders.

The study, completed in 2005, evaluated ecosystem restoration, flood control improvements, and river park trail development along a 7-mile reach of the Santa Cruz River from Congress Street upstream 7 miles. Planning objectives include increasing riparian wildlife habitat acreage and diversity, providing erosion protection where necessary, and providing passive recreation opportunities. 

In 2007 the study was authorized by the House and Senate as part of the Waster Resources Development Act, enabling future federal fund appropriations for design and construction of the project.

Recommended Plan Overview

The Recommended Plan includes 1,100 acres of mesquite bosques on river terraces and floodplain, bordered by palo verde woodland and desert shrubs on both banks. Implementation will consist of land re-contouring to enhance passive water harvesting. Supplemental irrigation will be provided to aid in establishment and as needed to maintain healthy plant communities. 

Flood control improvements included erosion protection that will be limited to at-risk areas. Recreation elements will include trail linkages to complete the Santa Cruz River park trail throughout the study area. Trails will also link to the existing Julian Wash Trail.

The plan features are consistent with the desires expressed by public involvement work groups. Implementation of the plan is supported by the U.S. Fish and Wildlife Service, Arizona Game and Fish Department, Center for Biological Diversity, Santa Cruz River Alliance, Tucson Herpetological Society, and others. 

Project Costs

Per federal guidelines, the ecosystem restoration features are a 65% federal/35% local cost share. Recreation elements are a 50/50 cost share. Total project construction cost will be about $92 million. Of the $32 million non-federal share, $26 million is accounted for by the sponsor’s land contributions, leaving $6 million as the local sponsor's cash commitment. Existing local funds include $14 million in dedicated 2004 bonds. The project was recently authorized as part of the federally approved Water Resources Development Act (WRDA) 2007 bill, enabling future federal funding requests.

The Pima County Regional Flood Control District has begun preliminary design on the Phase One, Ajo to 29th street reach.