Wright Water Engineers

Flood Risk Management Representative Experience

Scope of Services

Floodplain Modeling and

Mapping

CLOMRs/LOMRs/other LOMCs

Risk Assessment

Flood Control Structures

Reservoirs and Detention Facilities

Modeling

Post-wildfire Hydrology

Storage Volume

Sediment Transport and Loading

Source Estimate/Control

Stormwater Quality

Debris Flow Characterization and

Management

Alluvial Fan Flooding

Expert Testimony

Forensic Flood Assessment

Starting in the 1960s, Wright Water Engineers (WWE) has been responsible for numerous floodplain modeling projects and regulatory floodplain assignments including Conditional Letters of Map Revision (CLOMRs), Letters of Map Revision (LOMRs) and Flood Hazard Area Delineations (FHADs). WWE has extensive experience with floodplain and floodway regulations and policies and those who regulate them, including the Federal Emergency Management Agen-cy (FEMA), the Urban Drainage and Flood Control District (UDFCD) and the Colorado Water Conservation Board (CWCB).

WWE is a member of the Colorado Association of Stormwater and Floodplain Managers (CASFM). We employ 14 Professional Engineers, 2 Certified Flood-plain Managers, 4 Certified Professionals in Erosion and Sediment Control, 2 Licensed Appraisers and 2 LEED Accredited Professionals.

Wright Water Engineers

2490 W. 26th Ave. Ste. 100A Denver, CO 80211

Phone: 303-480-1700 Fax: 303-480-1020 E-mail: jonjones @wrightwater.com

Invesco Field LOMR

WWE was hired by HNTB and Turner Construction following the construction of Invesco Field at Mile High after a certificate of occupancy could not be obtained due to the fact that neither a CLOMR nor a LOMR had been filed for the facility, which sits at the confluence of the South Platte River, the Sloans Lake Overflow and Lakewood Gulch. WWE was hired to conduct model-ing and prepare a request for a LOMR as quickly as feasible. WWE coordinated closely with the City and County of Denver, UDFCD and their reviewer, ICON Engineering, to obtain this LOMR.

The project was especially challenging because construction of various compo-nents of the project was done using three separate vertical datums. WWE worked with HTNB, Turner and the Stadium Authority to develop a flood-proofing/emergency response plan. A LOMR was issued for the project.

Over the past several years, WWE has been working with South Dakota-based planning firm Confluence and the City of Sioux Falls, South Dakota, on redevelop-ing the greenway along the Big Sioux Riv-er through Sioux Falls. WWE has served as floodplain consultant for the project, which has been extremely challenging due to heavy urbanization and because much of the City was developed along the Big Sioux River corridor before the advent of

modern floodplain regulations. There are numerous structures that are currently in the 100-year floodplain and a handful that abut the floodway.

To date this project has involved considerable planning and multiple meetings with FEMA Region 8 officials and Michael Baker, Jr., Inc. (FEMA’s technical re-viewer for the project) to define ground rules for what may or may not be ac-ceptable for greenway improvements that encroach into the regulatory floodway.

Sioux Falls, South Dakota, Big Sioux River Greenway CLOMR

Wright Water Engineers

Flood Risk Management, continued

Wright Water Engineers

Denver 303-480-1700

Glenwood Springs 970-945-7755

Durango 970-259-7411

Blue River CLOMRs/LOMRs

Over the past five years, WWE has worked on four LOMRs and CLOMRs on the Blue River in and near Silverthorne, Colorado. In 2006, WWE performed modeling analysis for a proposed bridge across the Blue River in Silverthorne, Colorado, for the Angler Mountain Ranch development. WWE’s work involved revision of the 100-year floodplain

and floodway and a CLOMR submittal followed by a LOMR submittal, both of which were approved.

WWE was hired in 2006 by Compass Homes Development of Silverthorne to provide services for floodplain permitting and scour analysis for a new bridge across the Blue River for access to a new development. This assignment in-volved preparation of a CLOMR that was approved in 2007, which included modi-fication to both the existing floodplain and floodway and preparation of a LOMR approved in 2008 following completion of the bridge.

In October 2011, WWE completed a CLOMR request for Segment 5 of the Blue River Trail for the Town of Silverthorne. Because of constraints related to eleva-tions and property ownership, portions of the trail run through the 100-year flood-plain and encroach on the floodway for a boardwalk segment of the trail. WWE was teamed with DHM Design and Ten Mile Engineering, Inc. The trail alignment was hydraulically modeled by WWE using HEC-RAS to evaluate alternatives for the trail alignment. WWE assisted the town with preparing a report, mapping and paperwork to request a CLOMR from FEMA.

In 2012, WWE is assisting a developer with floodplain development permitting along the Blue River. A portion of the property is currently mapped in the 100-year floodplain. WWE will be working with FEMA and the Town of Silverthorne to fulfill the necessary permitting requirements for development that is planned adja-cent to a watercourse.

Jones Gulch Debris Flow Assessment

WWE has extensive experience in the analysis of debris flows. Our firm has done in-depth mud and debris flow hazard analyses and prevention planning in Pitkin County/Aspen, Colorado. We wrote the mudflow chapter of Aspen’s Criteria Manual and provided expert testimony on this topic for Aspen.

WWE was asked to develop a Debris Flow Mitigation Plan for a planned devel-opment near Keystone, Colorado, the Estates at the Alders. The development will be downstream of the debris-flow-prone Jones Gulch. The preliminary plat for the Estates at the Alders was approved in 2011, but one of the requirements for final approval was the Debris Flow Mitigation Plan we developed. WWE worked with H-P Geotech and S.A. Miro to fulfill the requirements of Summit County and the Colorado Geological Survey.

WWE performed modeling analysis for a proposed development along the Dolores River, West Creek and John Brown Creek in Gateway, Colorado. This CLOMR submittal included revision of the 100-year floodplain and floodway on West Creek and established the floodplain and floodway along the other streams. The CLOMR request was submitted in 2009 and approved in 2010.

On behalf of this client, Dr. Andrew Earles of WWE provided expert testimony at a CWCB Rulemaking Hearing regarding grandfathering provisions for CLOMRs based on a one-foot-rise floodway in new floodplain regulations.

Gateway Canyons CLOMR and CWCB Testimony

Representative Clients

UDFCD

Town of Silverthorne

HNTB

Turner Construction

Gateway Canyons

Confluence/City of Sioux Falls

Los Alamos National Laboratory

Boulder County

City of Golden

Rocky Flats Site

Coors Brewing Company

Jackson Kelly

Novak & Nelson Realtors