modern urbanized stream water quality improvement technologies

Modern Urbanized Stream Water Quality Improvement Technologies

Creating a Net Zero Water Quality Impact Solution in the Natural Environment

Navigating Agencies and Regulations

210-3-12Modern Urbanized Stream Water

Quality Improvements Technologies

• SWFWMD ERP

• Corps of Engineers

• Pinellas County

• NPDES

• Florida Game and Fish

• US Wildlife

• EPA

• Look for Common Goals and agreements. Par down Differences

• Identify and Resolve Issues Immediately

• Keep Constantly in Coordination with the Regulating Agency

• Completing Agreed Tasks on Schedule

Map Out the Road to Achieving Net Zero Impact


Quality Improvements Technologies3

DESIGN CONSIDERATIONS•Practices must be designed to effectively function over the entire range of urban stream flows, from baseflow all the way up to the maximum expected flow.•Hydraulic modeling is often needed to estimate current and project future design flows and flow velocities that structures must withstand.•The effect of each practice on channel hydraulics, sediment transport channel and floodplain capacity, and fish passage should be thoroughly evaluated.•Engineers should seek to provide a stable active floodplain to dissipate streamflow energy during high flows.•Deformable streambank treatments should always be considered in wider portions of the stream •Bank toes are normally the most vulnerable area of both bank treatments

•• The ultimate vegetative condition of the streambank and riparian areas influences local bank •dimensions. If these areas are managed in grass cover, they may produce a different bankfull width •than if they are fully forested.

•• Urban stream repair is still somewhat of an ongoing experiment, and every project should have •some form of monitoring or inspection to determine what worked, what didn’t, and why.



Get Out of the Box

• Urbanized systems require unique solutions

• Look to Combination of Solutions of Bioengineering and;

• Understanding that Vegetation alone does not always work and must also include evaluating engineered features



Curlew Creek Rehabilitation ProjectPinellas County, FL

• Resident structures are at or near the existing top of bank of Curlew Creek.

• Taking of property was not an option• Curlew Creek is a flash flood prone system and

has flooded the residential area several times• Residents are concerned with continued erosion

of the creek bank and bank slope instability• Culverts and box culverts are undersized and

aged and will need replacement• Solutions to resolve flooding, erosion and

improvement of the natural habitat included features such as:

• Expanded high flow creek sections

• Establishing bankfull flow and determining the low flow HGL

• The Curlew Creek is in a continual state of dynamic erosion and within 8 years between survey the creek bottom dropped an average of 1 foot

• A system to stop the continued lowering of Curlew Creek and enhancing the natural creek components became a priority



KEY PROJECT REQUIREMENTS

Beginning of Project



Project Tour: Channel D



Project Tour: Utilities



Project Tour: Kick Points



Project Tour: Channel A



Project Tour: Existing Crossings



Project Tour: Pristene System



Project Tour: Kick Point



Project Tour: Channel A Roughness Factors



Project Tour: End Project





Flooding and Erosion Issues

Urbanized Systems Require Unique Solutions



Reference: Technical Supplement 14R, “Design and Use if Sheet Pile Walls in Stream Restoration and Stabilization Projects”, Part 654 National Engineering Handbook

Sheet pile walls provide solutions where other stabilization applications would fail. Applications considered included:

•Toe wall scour protection

•Undermining protection

•Streambed grade stabilization

•Bank slope stability and Retaining walls

Typical Channel Sections

• Buried Gabion Matt Design Features under a Natural Habitat Rehabilation System



Typical Plan View with Cross Vane



Supporting Natural Processes with Engineered Features

“The final project maintains and allow the natural geomorphological processes to continue unimpeded in the natural flow condition in the low flow creek channel coupled with a buried protective backstop provided by a engineered gabion mat and rock vane system”



A Net Zero Impact Solution

• Final Project Features results in a Solution that Achieves the Common Goal

• Incorporates natural and bioengineered systems

• Supported with advanced engineered elements

• Results with a low flow ecological system and provides for erosion and flood protection



Questions?



modern urbanized stream water quality improvement technologies

Documents

stream bank toes

creek bank

water quality impact

urban stream repair

bank of curlew creek

optioncurlew creek

low flow hglthe curlew

flow velocities