Summary of Work Performed for the South Lee County Watershed

Plan Update (2009)

Presentation to Bonita Springs City CouncilBy

Roger Copp, A.D.A. Engineering, Inc.October 16, 2013

215 W. Verne Street, Suite D Tampa, FL 33606

Summary of Study Objectives

• Review Prior Studies• Identify Problem Areas• Develop and calibrate a Model for the South Lee

County area• Use model to identify flooding problems from Estero

south to Bonita Springs• Evaluate alternatives• Recommend strategy to increase flood flows to the

Estero River, Halfway Creek, and Spring Creek and reduce flows to the Imperial River

Study Area

Problems Identified

• Not enough flow to the Estero River and Halfway Creek

• Too much water east of I-75 north of the Bonita Springs NE Quadrant

• Flooding in Spring Creek east of Old US 41• Bridges over-topped in Spring Creek at Strike Lane

and Imperial Tributary at Pinecrest Lane• Flooding in Kehl Canal area and in Quinn/Dean Street

area of Bonita Springs

Final Recommendations

• Due to a variety of factors, the Update report remained draft for a period of time.

• Final recommendations were adopted on Jan 20, 2011 by Lee County and SFWMD.

• Recommendations pertinent to Bonita Springs are provided on the following slides

Final Recommendations(copied directly from Lee County/SFWMD document)

See Figure on next page

Map of Proposed Spring Creek

Improvements

Note that some of these recommendations may have already been implemented

Final Recommendations(copied directly from Lee County/SFWMD document)

See Figure on next page

Restore Flood Flows from Kehl Canal to Cocohatchee Canal

Additional Comments(personal opinions of Roger Copp)

• Additional storage is needed in the DR/GR area

• Additional storage would be beneficial for a number of purposes, including augmentation of public water supplies, holding back wet season flows for subsequent release during the dry season, and water quality treatment

• The area east of I-75 has historically been an area that experiences extended periods of flooding

• Realtors are normally quiet about how much flooding one can expect, so further development east of I-75 may result in more complaints to City Council

Bonita Springs SWMP Predicted 10-Year Flood Map

• Blue areas are flooded

Once in 10-Year Flood Map, Intera, 2010

Flooding East of Bonita Grande Drive

2010 SMP 10-Yr:

Aerial view:

Flooding East of Bonita Grande Drive

2010 SMP 25-Yr:

Aerial view:

Map of Simulated Water Levels During Fall 2006

The area east of the NE Quadrant is very wet, often for more than 6 months/year

1/1/06 7/2/06 1/1/07 7/2/07 1/1/08 7/1/080

0.5

1

1.5

2

2.5

Overland Flow Depths in DR/GR

61, 35 66_35De

pth,

feet

NE Quadrant Study Area

Measured Water Levels at Kehl Canal Gate

Key Take-Home Message: Water levels are the same on both sides of Kehl Gate