7th Avenue Creek has a history of flooding conditions, which have damaged homes and overtopped roadways, creating hazardous conditions and road closures. After several years of developing plans, obtaining grant funding, removing flood prone homes from along the creek, and finally designing and permitting improvement plans, the City completed our first significant construction project in 2021, which stretches from Washington Avenue at the southern limit to S. 10th Avenue at the northeastern limit. The project restored a natural meandering creek, stabilized streambanks, upsized culverts underneath Illinois, Indiana and South Avenues, removed a portion of S. 9th Avenue between E. Main Street and Illinois Avenue, and added a walking path along the creek between S. 10th Avenue and Indiana Avenue.
Native Landscaping – Establishment and Maintenance
Native landscaping takes upwards of three years to fully develop. Read below for expectations for the area by year:
2022 – “Sleep” Phase
The site is primarily a temporary cover crop and weeds. This is normal. Some native plants may be able to be spotted at this time.
The site is mowed at 8” height twice during the growing season, inhibiting reproduction of weeds and invasive species. Some plants are spot treated with herbicide.
The native plants are focusing their energy into their root networks.
2023 – “Creep” Phase
The weeds become lessened and native plants begin to spend energy on growth.
The site is mowed at 12” height once or twice during the growing season, along with spot treatment of herbicide.
2024 – “Leap” Phase
The native plants will now begin to out-compete the weeds and will be considered established at this time.
Mowing is no longer utilized except near trees, fences etc. that may be sensitive to burning.
Controlled burns are typically scheduled every 3-4 years once this phase is reached, which protect the deep rooted native vegetation and destroy shallow rooted invasive species and weeds.
Additional Project Background
In 2008, 7th Avenue Creek experienced significant flooding. The flooding caused large scale property damage and street flooding. The 2008 flood kicked off a series of events, including the Federal Emergency Management Agency’s (FEMA’s) floodway and floodplain re-mapping process and the City’s plan to reduce and/or eliminate flooding within the 7th Avenue Creek watershed.
FEMA has modeled a new floodplain, which is in its final stages of approval. The new floodplain maps became effective on July 20, 2021, mapping 42 residences and 15 commercial structures into the floodplain and floodway. The City’s improvements will allow the floodplain maps to be revised once again, this time removing several structures from the floodplain. Phases 2 and 3 of the 7th Avenue Creek project remain as future projects, which, upon completion, will remove the remaining structures from the floodplain.
Master Plan and Watershed Plan
The City completed development of a Master Plan in 2017, which outlines a construction project for the 7th Avenue Creek watershed that will not only remove all of the structures from the floodplain, but will also provide naturalized greenway areas along the creek, increasing water quality and restoring the creek to a natural state. In addition to the master plan, the City developed a Watershed Plan for 7th Avenue Creek (in conjunction with State Street Creek). This plan addresses stakeholder concerns within the watershed and provides recommendations of ways that water quality can be improved.
