Raccoon River Flood Water: What to Do First in Iowa

What has the Raccoon River done to this part of Iowa before?

The Raccoon River has flooded major parts of the Des Moines area. The Great Flood of 1993 flooded the city's water treatment facility and cut off the drinking water supply. Floods in the Raccoon River basin in 1986 and 1990 were also large, and the 1986 flood is the largest on record at several gauges in the basin.

The 1993 flood is the clearest example of what a river can do to a metro. It did not only put water into basements. It reached the systems the city depends on, and it showed that a flood can be a utility problem as well as a property problem. That is why river flooding is taken seriously across the metro, even by households that have never had water inside the house.

The 1986 and 1990 floods were driven by heavy rain across the basin. The 1986 flood is the largest on record at several USGS gauges in the basin, including Walnut Creek at Des Moines. These events are regional. A household that is not on the river bank can still be affected by runoff, high water tables and water that moves through the ground.

What are the first safety steps when river water is in the house?

Keep people out of the water, and do not enter a room with standing water and power still on. Shut off the power to the wet area at the breaker only if the panel can be reached without standing in water. If the panel itself is wet, leave it to an electrician or the utility. Keep children and pets clear of the area.

River water is often deeper and moving faster than it looks, and it can hide steps, debris and open holes. A basement stair that is under water can be a fall hazard, and an unseen object can cut or trip. Stay out of the water until the area has been checked.

Electrical hazards are the most immediate risk. Outlets, switches, a furnace, a water heater, a sump pump and any appliance that sat in the water can carry current even when they look dry. Do not plug anything into a wet outlet, and do not run a generator in the house or in an attached garage.

• Keep everyone out of standing water until the power is confirmed off
• Do not touch outlets, switches or appliances that stood in the water
• Do not run a generator inside the house or an attached garage
• Wear boots and gloves if you must walk through water that has silt in it
• Wash hands and skin after any contact with the water

What should be photographed before anything is moved?

Photograph each room from the same corner, the water line on each wall, the damage to floors and finishes and every item that will be removed. Take wide and close pictures and note the time. Those images are the first part of the record an insurer will ask for, and they are impossible to recreate once the water has gone.

Photographs made before cleanup show the depth of the water, the silt line and the damage that is hidden once carpet and drywall are removed. Include the outside of the house too, especially where the water came from, such as a window well, a walkout door or the grade toward the foundation.

Keep a written list of each item that was removed and why. A simple list with the room, the item, its condition and a photograph is enough. Do not throw away items that might be claimed until the list is complete and the insurer has had a chance to see it.

How does pumping work on a river flood?

Pumping removes standing water so the structure can be measured and dried. The pump rate and the discharge point matter. Pumping too fast can put pressure on soaked foundation walls, and discharge that flows back toward the house can refill the basement. Crews set the rate and the route before the pump starts.

Water that has soaked into the soil around a foundation pushes back against the walls when the basement is emptied. If the basement is pumped quickly while the ground is still heavy with water, the difference in pressure across the wall can cause damage. A measured pump rate protects the walls and keeps the work safe for the crew.

Discharge is the other half of the job. Water pumped onto a lawn can run back to the foundation, and water pumped toward a neighbor can create a new problem. The route is chosen so the water moves away from the house and does not return to it.

Is the water clean or is it sewage?

Clean water from a supply line is handled one way, river flood water is handled another, and sewage is handled with the most care. A water sample is not a homeowner's test. The signs that point toward sewage include a strong foul smell, a visible waste or paper in the water and water that has backed up through a drain. Treat any doubt as contamination.

River water is not automatically sewage, but it can carry sewage from broken lines, overflowing systems and flooded areas. A river flood can reach a sewer connection or a floor drain that backs up. Once that happens, the water in the basement is no longer just river water, and it has to be handled as contaminated.

Handling depends on the category. Contaminated water needs protective equipment, removal of porous materials that stood in it and a sanitizing step on the surfaces that remain. The crew decides the category on the first visit and records the reasons, so the homeowner can see why the handling changed.

Why is speed important, and what is the drying window?

Moisture that stays in a structure starts to change its materials, and it can support mold. The sooner standing water is removed and drying starts, the more materials can be kept. There is no fixed hour that marks the end of a safe window, and the crew judges progress by readings rather than by the clock.

River water can take a few hours or many days to leave a property, depending on the ground and the drainage. A basement that stays wet for a long time can have its framing and insulation damaged. The earlier the water is removed and the moisture measured, the better the chance that the materials can be dried in place.

The drying window is not a fixed number of hours. It depends on the materials, the depth of the water and how far the moisture has reached. A crew that starts early can measure the structure and set the plan, and a homeowner who calls early gives the crew more options.

When should I call, and what should I expect?

Call as soon as water is found, even if it is still going down. The water damage line is answered at any hour. A crew is sent when one can be arranged, and no arrival time is promised. On the first visit the crew confirms the safety of the area, decides the category of the water and sets the removal and drying plan.

Expect the first visit to focus on safety, the source, the water category and the removal. Measurements and the drying plan follow. The crew explains each stage and writes it into the scope, so the homeowner knows what is happening and why.

Ask the crew to show you the readings and the plan at the end of the first visit. Keep a copy of the scope and the photographs. Those documents help with the insurer and make the rest of the work easier to follow.