FLOOD11630 ‎(2)‎

• County: Statewide
• Basin: Arkansas
• Title: Post Flood Assessment Report - Arkansas River
• Date: 9/15/1999
• Floodplain - Doc Type: Flood Documentation Report

Wainings in effect, the ongoing flooding along the Arkansas and the Purgatoire R.ivers in Otero,
Crowley, Bent and Las Animas Counties, and the potential for flooding downstre~am of John
Martin Reservoir. That day, Significant Weather Outlooks addressing the floodin~g were issued
at 7 AM and noon. By the afternoon of May 5, 1999 all ~oints along the Arkansas and
Purgatoire Rivers had dropped below flood stage and no further flooding was occurring. At that
time, a final statement was issued canceling the Flood Warning for the Arkansas ~md Purgatoire
Rivers. No further statements were issued for the Arkan~as River downstream of John Martin
Reservoir since no flooding problems were occurring.
In addition to the aforementioned reports and advisories, the National Weather Se.rvice (NWS)
issued a number of Short Term Forecasts addressing the heavy rain and flooding that occurred in
southeast Colorado in late April and early May. It also participated in numerous coordination
calls with Emergency Managers, local law enforcement agencies, the Colorado Division of
Water Resources, the Corps of Engineers Albuquerque District and the Arkansas-lE~ed River
Basin River Forecast Center. These coordination calls were vital for maximum distribution of
timely flood and weather information to Federal and local emergency management personnel.
The coordination calls allowed all parties to participate in a direct excnange of information in a
highly efficient manner. Emergency Managers and law enforcement personnel provided the
NWS with valuable flood damage information while receiving the latest rainfall a~ld stage
forecasts. The Colorado Division of Water Resources provided the NWS with tirrxely and regular
stage data at several points along the Arkansas where critical river gages had been daznaged or
destroyed. This data was essential to the integrity of the river stage forecasts issu~d by the River
Forecast Center. In return, the NWS provided the Colorado State Division of Water Resources
with their latest forecast considerations regarding the heavy rain and flooding. ThP Albuquerque
Corps of Engineers provided the NWS with important information regazding necessary releases
from John Martin Reservoir.. In exchange, ihe NWS provided the Corps with the latest synopsis
and forecast information that they needed. Finally, coordination with the Arkansa:~-Red River
Basin River Forecast Center played an extremely vital role in the quality of service: provided by
the NWS to tiie emergency management community. The Forecast Center provided valuable
river stage forecasts and expertise that allowed NWS to issue accurate forecast infc~rmation. The
NWS was able to assist the Forecast Center by providing river stage data obtained from the
Colorado State Division of Water Resources and reservoir release information received from the
Corps of Engineers. All information exchanges during the event were mutual and benefited the
entire emergency management community.
OPERATIONAL CONSTRAINTS AND DEPENDENCIES
There aze unique aspects about the watershed that create constraints and dependenc:ies on and
between local flood management systems. Some of these aspects constrain the alte:rnatives for
local flood control improvements without a comprehensive basin wide study approach. The
following pazagraphs provide some understanding of the complex issues that must be considered
for any improvement to the flood management system. Appendix B and C provide; information
on environmental and cultural resources that exist within the watershed which can also influence
Chapter 3- Flood ofApri12.9, 1999
Post Flood Assessment Report ~ 27 Draft Revised ~D9/09/99