Skip to main content

Stormwater Master Planning#

Poudre River Whitewater Park

Stormwater Basin Master Planning Process#

Step One

Step 1: Baseline Hydrology

Determine peak runoff resulting from a 100-year rainfall event in the drainage basin.

Step 2

Step 2: Hydraulic and Flood Hazard Area Delineation (FHAD)

Perform hydraulic analysis to determine flooding extent resulting from runoff determined in the Baseline Hydrology. When appropriate, this information is used to complete the FHAD.

Step 3

Step 3: Selected Plan

Complete alternatives analysis to evaluate potential solutions to address flooding issues identified in the FHAD. Prepare conceptual design of recommended plan of improvements.

Step 4

Step 4: Master Plan Adoption

Final master plans are presented to Water Board and, for select basins, Larimer County Board of Commissioners for approval and then adopted by the Utilities executive director

Current Master Plan Updates#

The City is currently updating the master plans for the West Vine, Canal Importation, Upper Cooper Slough and the Foothills Basins.  Updates to additional stormwater basin master plans will occur each year as funding allows. Below is a table of master plan updates for the next two years. 


Basin Update


Spring Creek Hydrology, Hydraulics and Selected Plan


Fossil Creek Hydrology, Hydraulics and Selected Plan


Dry Creek Selected Plan


Mail Creek Selected Plan


McClelland’s Selected Plan


Fox Meadows Selected Plan

Regulatory Floodplain Overview#

As a participant in the National Flood Insurance Program (NFIP), the City of Fort Collins has adopted floodplain regulations that meet or exceed federal and state standards. The NFIP encourages states and communities to implement a floodplain management program that establishes floodplain requirements that are more stringent than the minimum standards set by the NFIP. In Fort Collins, flood risk is identified by mapping both FEMA and City floodplains. The FEMA floodplains include the larger drainage basins while the City Floodplains include some of the smaller drainage basins. 

Floodplain Regulations help protect people and property from the impacts of flooding.

Build responsibly: know the floodplain regulations. A floodplain use permit is required for any new construction, additions, remodel, filling or grading.

Improvements identified in the master plan, when constructed, reduce the flood risk. Floodplains are remapped after capital projects to identify properties still at risk for flooding. After construction, properties that are no longer mapped in the floodplain will not have to comply with floodplain regulations.

Learn More

Drainage Basins#

Drainaige Basin Maps

Click map to enlarge.


The City updated all the basin master plans and floodplain maps following the devastating 1997 flood. This included reviewing and updating its 100-year storm rainfall criteria. A “100-year storm” is a rainfall event that has a 1% chance of occurring in any given year.  

During the master plan update, analyses revealed that, approximately 2,745 structures and a large number of collector and arterial streets in Fort Collins are within the 100-year flood boundary and subject to flood risk and damage during a 100-year storm.

Stormwater Improvement Projects#

The basin master plans identify construction projects needed to reduce flood risk. These projects are categorized and prioritized in a Capital Improvement Project list. The Stormwater utility has constructed over $100 million of stormwater improvements since 1995.

Based on current funding, construction of these improvements is anticipated to be completed by 2050. The total cost for all the stormwater improvements is estimated at approximately $300 million.

The result of this investment in the City’s stormwater infrastructure will be a reduced flood risk to more than 2,300 structures with flood damages reduced by more than $600 million (2020 dollars).

View Past Stormwater Improvement Projects

Did You Know?

Planting fast-growing vines is a quick way to block unwanted summer sun. You'll get results in months.

You can reduce ‘vampire’ power waste by unplugging electronics that are not in use or plugging them into a smart power strip.

The watersheds where our water comes from drain snowmelt and rainfall to the Cache la Poudre and Big Thompson rivers and Horsetooth Reservoir.