Safeguarding Against Spring Thaw Flooding and Storm Damage

Spring is now officially here, and as the warmer weather settles in to stay, the winter season’s snow can melt rapidly, pushing rivers and streams to the brink and dramatically increasing the risk of flooding. Given the historic floods in 2013, every district should be prepared to deal with flooding from all sources. Several sources of potential flooding to consider are:

Spring Thaw

Even though warmer temperatures will initially melt snow, the ground will remain frozen and runoff will not be as easily absorbed into the earth. Each cubic foot of compacted snow contains gallons of water. Once it melts, the water can result in the overflow of streams, rivers, and lakes that flood nearby homes and businesses.

Hail Storms

When most people think of potential hail damage, they worry about protecting their vehicles and roofs. However, hail storms pose yet another risk: increasing flooding danger by clogging storm water inlets and impeding surface drainage.

Ice Jams

Long cold spells can cause the surface of rivers to freeze. When a rise in the water level or a thaw breaks the ice into large chunks, these chunks can become jammed, which creates a dam that blocks the flow of water and causes flooding upstream.

Spring Rains

Spring storms can bring several inches of precipitation in just hours or can stall out over an area for days. These heavy rains can lead to severe flooding by oversaturating the ground, overfilling storm drains, or causing rivers or lakes to spill over their banks or levees.

Levees and Dams

There are thousands of miles of levees and dams throughout the country that are designed to protect against a certain level of flooding. These structures can erode and weaken over time, and they can also be overtopped—or even fail—during larger flood events.

Flash Flooding

A flash flood is the rapid flooding of low-lying areas in less than six hours, which is caused by intense rainfall from a thunderstorm or several thunderstorms. Flash floods are a serious risk in drier climates like Colorado’s.

Flooding Terms Textbox

Being Prepared Makes All the Difference

It is important for Colorado special districts to be aware of where their property lies in relation to potential flood zones and to be prepared. Streams, reservoirs, and lakes that are often used for recreation are at risk of overflowing from spring snow melts, so special districts should post signs in these areas warning of the possibility of flooding.

Additionally, snow melt can result in roof and gutter damage. Extreme temperatures throughout the winter can severely abuse roofs, and damage can occur suddenly and without warning. Now is the time to inspect roofs for damage and make any necessary repairs. Next winter may seem like a long way off, but it will be back before you know it.

The CSD Pool automatically provides basic flood coverage for scheduled property, and has numerous options for more comprehensive flood coverage. This makes it even more important to schedule your property to avoid a loss to your critical infrastructure, such as underground service lines. If your district received FEMA funds in the 2013 flood, you will now be required to purchase coverage in order to be eligible for FEMA funds in the future. For more information about our flood coverage, contact us.

floodmaps

At right is a sample flood map for Boulder, which can be downloaded from FEMA’s website. Similar maps are available for all locations marked in blue in the map on the left.

To search for detailed flood maps in your area, visit FEMA’s website.

Flood Hazard Checklist

1.)Know Your Flood Hazards

    • Identify the flooding sources nearest to your district
    • Find out how deep floodwaters can get in your area
    • Learn where fast-moving or debris-filled water is most likely to occur
    • Determine the best ways for you to get a flood warning
    • Understand that floods can occur with little or no warning
    • Find out what streets are likely to be flooded or barricaded in and around you

2.) Purchase a water alarm if flooding may come from sewer back-up or basement seepage. The alarm can give you extra time to keep your damage to a minimum. A water alarm costs about $25 and is similar to a smoke alarm that will beep when water touches it. It is available online or at hardware stores and would be eligible for the Pool’s S&LP Grant Reimbursement program.

3.) Prepare a list of emergency telephone numbers, including the number for your insurance coverage contacts. Make copies and keep them in your car, at work, at home, and other locations to help ensure you have access to this information whenever and wherever you need it.

4.) Assemble the supplies you will need for cleanup and recovery and put them in a safe place that will stay dry during a flood.

5.) Install a National Weather Service (NWS) or Emergency Managers (EMs) weather information network that automatically receives weather updates (including flood watches, warnings, and advisories).

6.) Install automated precipitation and stream flow gauges. Information from these gauges can be transmitted directly to the district, giving a real-time view of rainfall and stream levels.

7.) Set up an agreement with the local radio stations to broadcast emergency messages to the public.

For an online version of the City of Denver’s handy Flood Protection handbook and other resources, please visit http://www.denvergov.org/Portals/428/documents/Denver_Flood_Protection_Handbook.pdf.

 

 

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