1

Stormwater Policy Overview

Presentation to the Winfield Board

Version 1

Winfield Stormwater CommissionFebruary 17, 2011

2

Purpose

How stormwater and drainage works

Background on the Winfield Creek and WBDR Drainage Basins – implications for Winfield

Overview of policy options

Flooding – The Big Picture

Stormwater-related flooding is actually 2 issues:

Drainage – localized and due to grade or poor construction• The Winfield Stormwater Commission has

developed a system to prioritize and deal with drainage issues

Floodplain flooding – affects properties in the floodplain due to rain events

Floodplain flooding is the focus of this presentation 3

Stormwater and Drainage

4

5

Watersheds

Watersheds are the land area that drains water to a particular stream, river, or lake

It can be identified by drawing a line at the highest elevation between two areas –this defines the drainage area of the watershed

http://www.gocolumbiamo.com/PublicWorks/StormWater/Watersheds/

Watersheds are key to understanding stormwater and stormwater impacts

6

http://edeninitiative.com/watersheds.htm

Watershed SchematicKey features:•Watershed divide•Tributaries•Sub basins

Winfield is at the receiving end of our drainage basin AND the WBDR

Impact of Development

7http://www.cityftmyers.com/Departments/PublicWorks/Divisions/Engineering/Information/StormwaterInformation/tabid/340/Default.aspx

8

• WBDR and Winfield Creek are part of the Des Plaines River Watershed

• WBDR is 127 square miles, and Winfield Creek is ~9 sq miles

• Watershed land is nearly fully developed, with residential, commercial, and open space land use

West Branch of the DuPage River Watershed

Source: Fig 2-1, (draft) DuPage West Branch DuPage River Watershed Plan (12/2/2005)

9

Winfield Creek Watershed

Source: Fig 2-1, (draft) DuPage West Branch DuPage River Watershed Plan (12/2/2005)

Winfield

10

Why Winfield FloodsDrainage Basin Land Use

Most land use is residential with some light industry, commercial, transportation and open space

18.3% of the land is ‘impervious surfaces’

Watershed is prone to flooding due to very flat slope (average 6%) and development (impervious surfaces)

Source: (draft) DuPage West Branch DuPage River Watershed Plan (12/2/2005)

Stormwater Policy

Origins of stormwater policy in DuPage County and Winfield

What DuPage County has identified as stormwater options for Winfield

What Winfield is doing

11

Origins of Stormwater Policy DuPage County - Flooding event of 1987 –

caused the County to enact the Stormwater Ordinance• Caused formation of the DuPage Stormwater

Commission in 1992 2008 flood event – caused major impacts

in DuPage County and especially in Winfield • Resulted in the formation of the Winfield

Stormwater Commission in 2009 DuPage County plans a major update to

the Stormwater regulations by January 2012 12

DuPage County Options and FundingFunding: not established. Report notes funds are

needed from developers, property owners, municipalities, and County

• Flood proofing – when property not meet buyout criteria. Need policy

• Buyouts – for flood damaged property when buyout criteria met, most cost effective, and no flood control available

• Land acquisition – to be done when ‘green space’ needed for riparian corridor

• Flood control – when regional benefits are cost effective. Funded by County

13Source: (draft) DuPage West Branch DuPage River Watershed Plan (12/2/2005). Appendix A

DuPage County Options for Winfield

The County has identified the following options for Winfield:

Buy-outs FloodproofingWaiting list is long, scarce funding,

significant requirements

Currently there are no County plans for stormwater flood control for Winfield

14

Winfield Actions Drainage-related flooding

• Established procedure to increase transparency and efficiency of allocating Village resources

Floodplain flooding - a regional problem• Solution: engage with the County• Let them know we have a problem (squeaky

wheel)• Work with County to identify ‘next step’

15

Winfield Actions

Path Forward – work in progress…• Update 1993 Winfield watershed

evaluation• Identify what Winfield would propose to

county to address floodplain flooding

16

End of Presentation

17

Support Material (use if needed)

18

19

WBDR and Winfield Creek Watersheds

1. WBDR and Winfield Creek are part of the Des Plaines River Watershed

2. West Branch watershed covers 127 square miles at the confluence with the East Branch DuPage River, which flows into the DuPage River

3. The West Branch watershed covers much of DuPage County and includes 17 tributaries

• The largest tributary is Kress Creek at 18.4 square miles.

• The Winfield Creek tributary is 8.5 square miles (or 5,420 acres)

Source: (draft) DuPage West Branch DuPage River Watershed Plan (12/2/2005)

20

Winfield Creek Watershed Description

• ~8.5 square miles• Includes Winfield, Carol Stream, Glen Ellyn, Glendale

Heights, Wheaton, DuPage County Complex, unincorporated areas

• Mostly residential with commercial and undeveloped (park districts and FP)

• Some wetlands at headwaters• Confluence with WBDR at west end of Winfield

Major flooding areas• General: are within floodplain and are limited to a small

number of structures. Causes traffic disruptions, property damage, and sewer backups

• Confluence of Winfield Creek and WBDR. Six other problem areas noted. 21

Source: (draft) DuPage West Branch DuPage River Watershed Plan (12/2/2005). Appendix A

Impact of Development Impervious surfaces

(roof, road) and less pervious surfaces (lawn, compacted soil) prevent water from being absorbed, causing increased runoff

Results in increased flooding severity, and decreased water quality

22http://www.cityftmyers.com/Departments/PublicWorks/Divisions/Engineering/Information/StormwaterInformation/tabid/340/Default.aspx

Stormwater Problems Historic flooding has caused damage. The report

notes the 1996 flood, which did extensive damage to downtown Naperville

Floodplains and floodways protected by federal, state, and county law and also by local ordinances.

The DuPage County Forest Preserve owns large amounts of land in the floodplain, which helps reduce damage due to flooding

Water quality and biodiversity are impaired

23Source: (draft) DuPage West Branch DuPage River Watershed Plan (12/2/2005)

24

Stormwater Policy Options Based on alternatives outlined in the

WBDR Watershed Plan (draft, 12/22/2005) as noted in the Winfield Creek discussion in Appendix A

Appendix A of this report included summaries of the Winfield Creek sub-basin watershed plan (April 1994)

Winfield Watershed Options

• For Winfield area, County provide assistance with floodproofing in accordance with Countywide flood proofing policy (implemented?)

• Areas upstream of Winfield are divided into segments 2 to 9, with Winfield being segment 1 For segments 2 to 9, generally recommend

Alt 3 (buyouts w/flood control), with one segment for Alt 1

25Source: (draft) DuPage West Branch DuPage River Watershed Plan (12/2/2005). Appendix A

26Source: (draft) DuPage West Branch DuPage River Watershed Plan (12/2/2005). Appendix A

Winfield Watershed Options Alternative Analysis

• No action• Alt 1: Floodproofing without land acquisition.

Some buyouts* (residential only)• Alt 2: As Alt 1, but with land acquisition.

Establishes ‘green space’ in continuous corridor• Alt 3: Buyouts with flood control measures

Winfield-area recommendations• Heavily influenced by WBDR• Recommend Alt 1, but with no buyouts• Evaluate in greater detail when WBDR main

stem study completed27

Source: (draft) DuPage West Branch DuPage River Watershed Plan (12/2/2005). Appendix A

Dams on the WBDR 5 dams (circa

2003) Warrenville and

McDowell Dams removal (funded 2008)

28

http://www.dupagerivers.org/dampage.html; Assessment of the Impacts of Dams on the DuPage River; Conservation Foundation, Oct 2003

29http://www.dupagerivers.org/dampage.html; Assessment of the Impacts of Dams on the DuPage River; Conservation Foundation, Oct 2003

Winfield Creek confluence ~710 ft amsl

Note – it is highly unlikely that the Fawell Dam has any effect on flooding in Winfield

Fawell Dam Pool and GW Elevations

30http://ec.dupageco.org/dec/mainstFawell.htm