Grant Frontier – Overland Park Project Update 7-29-2016

Work is moving along on the Grant Frontier Portion of the project. 7/2016

Grant Frontier looking North.  Denver Trout Unlimited is funding placement of an additional rock cluster that was removed due to increased costs.

 

Construction photos from Ronnie on the Overland Section

Click the photo to see all Ronnies River Reports on the Grant Frontier construction.

 

Help Spend $5 Million in the Denver S. Platte

Grant Frontier - Overland Park Project

Member Meeting presentation 1/22/2013

By:

 

Brian Murphy is a Water Resources Engineer with CDM Smith in Denver, Colorado. His primary fields of work include river engineering and aquatic ecosystem restoration. Brian is a licensed Professional Engineer in four states including Colorado; a Professional Hydrologist; and a Certified Floodplain Manager.  

Project Area is Grant Frontier to Overland Park.

 

The main project goal is to improve aquatic and riparian habitat by changing the channel’s geometry and creating wetland benches.  All land is owned by City and County of Denver, which means no land acquisition is required.

 

 

In the 2 mile stretch the current project cost is about $5M.

 

The banks are overgrown. A design goal is to open up the river so you can see it from the trail and provide stream access for boating. Cottonwood trees and other native vegetation will remain to help cool the river.

 

A design goal is to turn these urban parks to a more high plains environment. That means no bluegrass.

 

 

The Florida Avenue Drop.

 

The Florida drop was constructed in the 1970s to divert irrigation water for  Overland golf course.

Currently it holds 5 ft  of sediment and little water is being impounded. Basically it is a 150 ft wide very flat duck habitat, not an aquatic habitat. Sediment will be removed and used to create alluvial bars.

 

The Florida drop will be removed and replaced with an active channel, smaller riffle drops and pools which create high and low stream velocities. Habitat work will accommodate low flows, with emphasis on micro habitats and complexity. In reviewing working drawings keep in mind that the CDM Smith draftsman was a kayaker.

 

Pasquinel’s landing park.

A side channel will be created to filter and create a flood plain, and scour hole behind rocks will be created.

The focus of the design seems to be on happy habitat for fish without much concern for bug habitat.  Much of water in this section of the S. Platte is from a nearby wastewater treatment plant. This yields a constant flow but is high in nutrients. The stream improvements will help increase the dissolved oxygen in the stream. A problem is that in this area sediment can’t be pushed to into the floodplain because of the channel’s trapezoidal geometry. Trying to create a floodplain for sediment storage is impossible because of inability to open the channel up along overland golf course.

Vegetated riprap banks will be constructed during the improvement project and should help reduce the amount of erosion and sediment pushed downstream.

 

   What to expect to see in this area of the South Platte are:

 

  • Woody structure
  • Riffle pools
  • Bend way weirs
  • Rock vanes
  • Snags
  • Deflectors
  • Boulder clusters
  • Final Drawings by August, work to start Oct 2013, finish mid 2015.

 

Now is the time to suggest changes and additional concerns like:

  •  Include preferred habitats for fish, like trout, that would be at home here AFTER a Chatfield Reallocation project made it possible for the aquatic habitat to be maintained with minimum flows. Current use of Chatfield as a flood control project prohibits releases for habitat reasons.
  • Flow depth, velocity, and temp preferences for the BUGS should be included in the design.
  • No kayak stanchions in this area or overhead cables to impede casting.

Send these suggestions to Brian at- murphybm@cdmsmith.com

 

Additional Info:

Denver City – South Platte Corridor Study 

River Vision Planning Document.