An advisory committee meets as needed to review study progress and provide input. New committee members are welcome. Those interested in participation should contact Dave Wells at Dave.wells@greeleygov.com
Study information has been compiled into a draft feasibility report with technical appendices. Information previously compiled as "deliverables" for Colorado Water Conservation Board has been recompiled and expanded to include the "future without project" description. The technical review of the draft report is nearing completion and is expected in September 2009. Internal technical reviews for quality assurance and quality control have been completed on all technical work of the problem identification phase including existing conditions, future without project, as well as the plan formulation of the Decision Point 1 alternatives.
The future without project (do nothing) conditions was completed in March 2009 yielding some unexpected results:
• Increase in size of frequent (2 thru 25-year) flood events is expected to continue, with 2-year flood peaks expected to be 37% higher after 2035 than current floods.
• Channel aggradation from sediment build-up is expected to increase flood stages in Greeley in future floods, especially for more frequent events.
• Any upstream water supply projects, such as NISP would tend to increase channel aggradation & lower flood discharges for some frequencies.
• Future Equivalent Annual Damages (EAD) increased from $1,266,000 to $2,379,000 based upon forecasted flood runoff and channel aggradation.
• Riparian ecosystem expected to continue to deteriorate, chiefly due to urban pressure and invasive species.
Free consultation to this project was provided by the Corps Research Lab in April 2009. The focus of this technical assistance was riparian ecosystem restoration, river morphology and sediment transport. Recommendations were made for additional geomorphology study.
Present work efforts are focused on completing plan formulation and evaluation, wildlife and wetlands survey. Other tasks to be performed before concluding the study include comparing alternatives, recommending a plan, agency technical review (ATR), and the Feasibility Scoping Meeting (FSM). Future study efforts will focus on improving flood damage reduction methods and solution economics and developing the best plan for viable ecosystem restoration of the Cache la Poudre River. In addition, cost-shared recreational facilities could be developed that are compatible with the Corps project and with current local and regional recreational planning efforts.
Anticipated study costs have increased from $1,560,000 to $2,420,000. The estimated time to perform the Study has grown from three years to six. Factors contributing to these increases were explained at an Executive Committee meeting on June 30, 2009. The Corps will be preparing a Schedule And Cost Change Request (SACCR) document. Scope increases include additional reports (CWCB deliverables), additional technical reviews mandated by Corps Headquarters, additional geomorphology analysis recommended by Corps Research Lab, and additional hydraulic modeling needed to develop operational HEC-RAS model. Cost increases are also attributed to difficulty in finding a Decision Point 1 alternative with benefit cost ratio greater that one, evaluation of several levee alternatives which had not been anticipated, and the longer study duration increases project management and program administration costs
Background
The US Army Corps of Engineers and the City of Greeley are conducting a Feasibility Study of the Cache La Poudre River in and near Greeley. The study area is lower seventeen miles of the river, ending at it's confluence with the South Platte River. The primary purpose of the study is to identify buildable projects that will reduce flood damages and/or improve wildlife habitat. Work on the study began in February, 2006. This multi-year study will cost an estimated $2,420,000. The initial estimate when the study began was $1,560,000. Costs are split 50/50 between the City and the Corps. The City has received $300,000 in grants from the Colorado Water Conservation Board to help with the City's share. So far, half of these grants have been spent.
A detailed investigation of potential flood damage reduction was conducted along the urbanized reach of the Cache la Poudre in Greeley. This was performed to determine if there was a likelihood of finding a viable flood protection project before all feasibility study funds were spent. This investigation has been referred to as "Decision Point I" or "Phase I". Decision Point I was requested by the City of Greeley as a precondition for signing the Feasibility Cost Share Agreement. Work on Phase I was completed in May 2008. It was determined that there is a likelihood of a flood protection project with a benefit to cost ratio greater than 1.0.
This past year, the study has been in a "catch-up" period, completing several significant tasks required of all Corps General Investigation Studies including the Agency Technical Review (ATR) of existing conditions, hydraulic and economic models.
A public meeting, following NEPA guidance, was required before moving forward with plan formulation. This was held Thursday evening, December 4th, 2008, at the Island Grove Event Center in Greeley. Attendance exceeded thirty. Numerous comments and questions were received from a roomful of interested property owners as well as various local government agencies. Five individuals from the U.S. Army Corp of Engineers from Omaha NE, presented background information in English and Spanish, and conducted an audience question, answer and discussion period followed by small group and one-on-one interaction with the attendees. The meeting focused on developing the Environmental Assessment portion of the feasibility study. It also covered hydrology, hydraulics, real estate and recreational areas.
An advisory committee meets as needed to review study progress and provide input. New committee members are welcome. Those interested in participation should contact Dave Wells at Dave.wells@greeleygov.com
Purpose:
The purpose of the feasibility phase is to fully define problems and opportunities, to develop and evaluate alternative plans, and to fully describe the recommended project. Since ours is a GI (general investigation) study, it can and does have multiple goals and benefits. Although we are not limited to flood control and flood damage reduction, it remains our main purpose. Other objectives include environmental restoration and enhancement, sediment management and inherently water quality improvement as well as developing recreational amenities. In addition, opportunities will be investigated for developing and accounting for attenuation of peak flows due to flooding of gravel pits and augmentation reservoirs.
Study
Objectives
· Flood Control
· Environmental Restoration
· Sediment Management
· Water Quality Improvement
· Recreation
· Detention storage/augmentation
Feasibility Study
Components
· Hydrology & Hydraulics
· Economic
· Environmental
· Real Estate
· Plan Formulation and Project Management
Benefits of Improvements
· Reduction of property damage
· Improved public safety
· Reduce private property in floodplain
· Eliminate flood insurance needs or requirements
Downloads
Meeting Summaries:
Maps:
Links:
U.S. Army Corp of
Engineers:
Omaha District: