Floodplain Management Program Notes

By Bill DeGroot, P.E., Manager, Floodplain Management Program

A Day at the District
On Wednesday, October 18, 2006, the National Association of Flood and Stormwater Management Agencies (NAFSMA) and the District , in cooperation with the Federal Emergency Management Agency (FEMA), held an event called "A Day at the Urban Drainage and Flood Control District".  The event was held in the District's board room.

This event was structured to present how the District implements its comprehensive floodplain management effort, and how FEMA’s Cooperating Technical Partner (CTP) program has assisted the District in its mission.  The program started with an overview of the District’s programs.  That was followed by a discussion of the District’s experience as a CTP and how that was integrated into the District’s programs.  That was followed with a presentation on Map Modernization. 

There were also live on-line demonstrations of the Mapping Information Platform (MIP) and DFIRM tools.  The final part of the day included a presentation of NAFSMA’s “Guidance for Municipal Stormwater Funding,” a round table question and answer period and a reception, where one-on-one and small group discussions continued.  Program materials are available at www.nafsma.org.

Public Information Program
For the past 25 years or so we have annually mailed flood hazard information brochures to addresses located in or near 100-year floodplains delineated by the District.  Each brochure was site specific and included a map of the floodplains for usually one, but sometimes several, drainageways using USGS quadrangle maps at a scale of 1” = 2000’.  Each brochure included specific information about the drainageway(s), sources for the floodplain information, local government contacts and phone numbers, and information about flood warning plans if the exist for the drainageway.  Also included was standard language about flood hazards, flood insurance and a section on “What can you do?”

This year we made a significant change in the format.  We still mailed brochures with all of the same information described above and tailored to a small number of drainageways each.  However, instead of a map of each drainageway we included instructions on how to access a floodplain map on our web site using an address search engine to show floodplains on a photo background and a star on the requested address.  The floodplain map is a compilation of all of the digital floodplains developed for completed or nearly completed Digital Flood Insurance Rate Maps (DFIRM’s)

See Bruce Rindahl’s excellent article elsewhere in this issue for more information on the technical aspects of this effort and first year results.

Floodplain delineation
We completed two flood hazard area delineation (FHAD) studies this year:  Clear Creek through Adams County and Massey Draw and SJCD (South) in Jefferson County.

We have FHADs underway for Clear Creek in Jefferson County, Dutch Creek and Tributaries in Jefferson County, Lower Lena Gulch in Wheat Ridge and Hoffman Drain in Adams County and Thornton.

All of these studies are prepared in digital form compatible with FEMA’s DFIRM specifications, and have been or will be incorporated into the appropriate DFIRMs.

DFIRM conversion projects
In 2004 we received FEMA DFIRM conversion grants of $480,000 each for Adams County and Arapahoe County.  The District has contributed $70,000 for each county and the Colorado Water Conservation Board has contributed $50,000 each.

The contractor for Adams County is ICON Engineering, and for Arapahoe County it is Merrick and Co.

Unfortunately, both projects have taken longer than anticipated, due primarily to the lack of backup data the Michael Baker Jr., Inc. library has been able to provide to us.  We have had to scramble to find other reliable sources and this delayed the process.  This was particularly true for Arapahoe County, where we had the additional problem of integrating Aurora and Littleton into the map.

The effective date for the Adams County DFIRM has been established at March 5, 2007.  We are still hopeful that Arapahoe County will go effective in late 2007.

In 2004, the District received a $240,000 grant from FEMA, to be matched by $30,000 each from the District and CWCB, to convert the Jefferson County DFIRM to the NAVD 88 datum.  This is not enough money to complete all of the required work and publish new panels, but it is a good start. The contractor is ICON Engineering

While we are at it we will use digital flood hazard area delineation study reports completed or underway to supplement or replace older data sources in the DFIRM.  This will include Ralston Creek, Leyden Creek, Massey Draw and North Tributary, SJCD (South) and Tributaries, Clear Creek, Lena Gulch and Dutch Creek and Tributaries.

The Boulder County DFIRM conversion project, which is being managed by the CWCB has also been delayed, but should go effective sometime in 2007. 

LOMC pilot project
On July 1, 2001 we began a pilot project with FEMA to assume the responsibility to review requests for Letters of Map Change for the 33 communities within the District that are participating in the National Flood Insurance Program.  We begin 2007 with a new grant to continue the project  Our final reports to FEMA on the results of the first four years are available on our web site.  The fifth year report will be posted in early 2007.

We completed a second DFIRM maintenance pilot project, this time concentrating on incorporating new LOMRs into DFIRMs, and being able to quickly and economically print revised paper maps.  This is in recognition that some communities and individuals still want paper products rather than digital ones.  Our reports to FEMA on both pilot projects are on our web site.

Maintenance Eligibility
Our maintenance eligibility program continues to flourish under David Mallory’s direction.  See David’s column elsewhere in this issue. 

Implementation efforts
Implementation of portions of our master plans, particularly regional detention facilities, is always a challenge.  We completed execution of an Intergovernmental Agreement (IGA) with Denver and Aurora regarding the implementation of regional detention facilities in the Upper Second Creek watershed.  We have also negotiated an IGA with Denver and the Rocky Mountain Arsenal (RMA) for the construction, operation and maintenance of a number of facilities on the RMA.  That agreement is in the signature process.

We saw significant progress in the Irondale Gulch watershed in 2006.  This is a particularly difficult area because there are no readily apparent major drainageways, and the entire drainage system has to be created from scratch.  Two regional detention facilities were constructed and a third was underway.  Also, approximately 9000 feet of open channel were constructed.  Most of the facilities were constructed by developers who will be reimbursed for their efforts through drainage impact fees.

FasTracks Coordination
We continued to work closely with the Regional Transportation District (RTD) on their FasTracks project to add over 100 miles of new light rail, commuter rail and bus rapid transit corridors to its system.

The first corridor scheduled for implementation is light rail along the West Corridor.  Portions of the alignment involve the South Platte River, Lakewood Gulch and Dry Gulch.  We have identified three master planned projects that we will implement, in cooperation with Lakewood and Denver, with or ahead of the rail construction.  We also recently completed our comments on RTD’s 65% design drawings.

We are also working with RTD and their consultants on environmental impact statements for three other corridors.

Check these out on our web site
We have a photo album showing what we consider to be good examples for others to emulate.  We also have an Activity Summary map that identifies all District studies completed or in progress.  We update the status of all our studies quarterly.  It would be a good idea for anyone working on a drainage study in the District to check this map for existing or on-going studies that might affect their work.