improving ecological stream functions & habitat
the wra fourmile creek improvements-north of broadway project protects vital infrastructure while fostering improved ecological functions and habitat. traditional infrastructure protection with riprap at single bends was abandoned because of the low ecological value. generally speaking, the ecological value of an organism, natural resource, activity, and other components of natural ecosystems are defined by the benefits they provide to support native life.
integrating ecological lift techniques within this complex project has garnered a 2019 engineering excellence honor award from the acec-ia.
this project began when streambank erosion at several fourmile creek locations put sanitary sewer infrastructure at risk. snyder & associates’ experience with environmental engineering, fluvial processes, and stream restoration prompted the des moines metropolitan wastewater reclamation authority (wra) to seek our assistance on a creative solution to address the issue. collaboration was essential in creating a vision for the project as well as identifying project priorities and opportunities.
by reading the river and using natural channel design concepts, this project transformed an environmental liability into an improvement that:
- boosts water quality through sediment loading reductions and vegetative filtering of nutrients
- strengthens the safety of stable/non-vertical banks
- reduces the risk of downstream flooding
- creates a user-friendly recreational environment
- enhances the aquatic habitat for fish and other living organisms
funding assistance strengthens project impact
wra embraced the opportunity to leverage srf sponsored project funding associated with their infrastructure improvement loans. as a result, they expanded a limited bank stabilization project to protect their sanitary sewer infrastructure into a comprehensive stream restoration approach that benefits longer reaches.
through several applications, we helped the wra secure $4.2 million in funding assistance to leverage their limited traditional funds. we were also able to successfully coordinate with multiple agencies and partners to facilitate right-of-way acquisition and meet funding requirements. over 8,000 feet of stream restoration was prioritized in three fourmile creek reaches—north of broadway avenue, north of euclid avenue, and south of university avenue—to reduce severe bank erosion and channel degradation, and protect sanitary sewer infrastructure.
