What is a "Conceptual Level Selected Plan"?

    A conceptual level design for a Basin Master Plan is a high-level early phase in the engineering design process. This level of design helps us better understand the overall potential project and its benefits and drawbacks. As a part of this process, the design team will identify, project cost estimates, large utility conflicts, impacted properties, potential stakeholders, and other project constraints. This high-level design process allows us to budget for these projects and prioritize them based on the community’s needs. Once a project is ready to be implemented, a more detailed design is conducted, building upon the conceptual level design, to bring the project design process to completion.  

    What is the 100-year floodplain and why is it important?

    How can the public impact the outcome of the plan update?

    The scope of work for this master plan update is to update the Alternatives Analysis and Conceptual Design using the 2014 updates to the hydraulics and hydrology, account for any constructed improvements, consider current design practices, and evaluate the basin in a more holistic approach including parks, trails, nature areas, and water quality opportunities. 

    The City Stormwater group would like your help to better understand where flooding has occurred in the past near your property.  As a part of this stormwater master planning update, we would like to approach our effort in a more comprehensive manner. We would like to hear about how you use trails in your neighborhood and your thoughts on potential open space and parks.

    What does "alternatives analysis" mean?

    Before a plan can be developed to address potential flooding in the basin, City staff and our consultants consider multiple possible options to address the flood risk along each flow path.  These various options comprise the different alternatives for the basin.  For this project, a conveyance alternative and a detention alternative will be developed for each flow path.  These alternatives each have both positive impacts and potential negative impacts.  The analysis of these alternatives, their engineering feasibility, and their potential impacts, comprise the alternatives analysis.

    What is "detention?"

    Detention Basin, Facility or Pond: The temporary capture and slow release of stormwater from an excavated area, enclosed depression, or tank. Detention is used for pollutant removal and stormwater peak flow reduction. Detention basins, facilities and ponds are considered to be “stormwater detention and infiltration facilities” under CRS §37-92-602(8). 

    Source: Fort Collins Stormwater Criteria Manual (2018)

    What is "conveyance?"

    Stormwater collection and conveyance systems are critical components of urban stormwater infrastructure. Proper design is essential to minimize flood damage and limit disruptions. The primary function of the system is to collect excess stormwater in street gutters, convey it through storm drains and along the street right-of-way, and discharge it into a detention basin, water quality best management practices (BMP), or nearest receiving water body. 

    Source: Federal Highway Administration (2009)

    After precipitation falls, naturally occurring drainage ways such as open channels, creeks, streams, serve to transport water downstream.  Other stormwater infrastructure often includes buried storm sewer pipes, culverts, and ditches.  These natural drainage ways and manmade systems serve as the conveyance infrastructure to transport water through urban neighborhoods.

    Source: Fort Collins Stormwater Criteria Manual (2018)

    What is the difference between hydrology and hydraulics?

    Hydrology: In a hydrologic analysis, the goal is to determine the peak runoff resulting from a rainfall event in the drainage basin. This can be done for many different size storms. This process uses hydrologic models to estimate rainfall, infiltration, and runoff for a watershed.

    Hydraulics: In a hydraulic analysis, the goal is to determine the potential flooding extent resulting from the runoff estimated in the hydrologic analysis. This process uses hydraulic models to estimate flow depth and velocity in channels, culverts, pipes, and through bridges.  

    Why is the basin called Canal Importation?

    The basin received its name because it is intersected by three major irrigation canals that predate most of the surrounding residential and commercial developments. The flooding in the Canal Importation basin is due to its urban nature and because development in the basin took place prior to the implementation of a City stormwater drainage program in the 1980s. 

    Source: Fort Collins Stormwater Criteria Manual (2018)