Welcome to the Drainageway Planning and FHAD Website...

Dutch Creek site photo

PROJECT BACKGROUND AND DESCRIPTION
(For an overview in PDF click here)

The Urban Drainage and Flood Control District, on an ongoing basis, updates Drainageway Planning Studies and Flood Hazard Area Delineations within the District to provide a basis for basin-wide planning and floodplain management. PBS&J was selected to perform the Major Drainageway Planning and Flood Hazard Area Delineation services for Dutch Creek, Coon Creek and Lilley Gulch. Also included in this study is the Three Lakes Tributary. The previous Planning Study and FHAD were completed in 1979 and 1978 respectively. The drainage basins for these drainageways have seen significant development over the last 25 years. One of the purposes of this study is to evaluate the impacts of this development and determine if the previous estimates for the basin under developed conditions were correct. Any changes in hydrology could also affect the floodplain delineations along the drainageways. The purpose of the study is to provide an updated hydrologic analysis and alternatives assessment and updated hydraulics and floodplain analysis. Work will include hydrologic modeling, hydraulic analysis, conceptual design, public involvement, natural resources and identification and utility coordination.

PRIOR AND ONGOING STUDIES

The previous Major Drainageway Planning study was completed in 1979. The Flood Hazard Area Delineation was completed in 1978.

STUDY CONSIDERATIONS

The primary focus of this study will be to develop a long-term plan for stream stability, detention and conveyance within the drainage basins and to update the flood hazard delineation along the drainageways themselves. Alternatives developed within this planning process will seek to meet the objectives listed below. Some of these objectives come from the original Drainageway Planning Study:

Update hydrology within the study area
Provide accurate floodplain delineations for the drainageways of concern
Develop alternatives for major thoroughfares crossing floodplains so that they are protected from impassable inundation during the 100-year event
Maximize the level of property protection and public safety
Provide for passive recreation, multi-use parks and linear trail access within the defined drainageways.
Where possible, address water quality impacts
Minimize negative environmental impacts such as 404 permitting, NPDES permitting and other Clean Water Act implications.
Minimize life cycle costs by minimizing initial capital outlay and providing for long term service life.
Encourage and enable development participation.
Provide flexibility in phasing.
Provide high benefit to cost ratios.
Provide a document that is rational and likely to galvanize public and political support for drainage improvements.