Sometimes I hear people say, “I bought a house on a hill so it doesn’t flood”.  While this helps, a house on a hill can still have issues with water due to localized drainage problems.  How can you tell if a property has a water issue before you purchase it?  The simple answer: drive by while it is raining.  And go talk to the neighbors.  Someone will let you know if there is a problem.  People can’t wait to talk about their drainage problems!

Flooding

The ponding water shown here is from a failing drainage system.

3 basic types of flooding

If you live near a stream or creek, then you have probably experienced flash flooding.  If not, then you have seen it on the news and heard the warnings about crossing the flooded road (which people feel compelled to ignore). This type of flooding is caused by heavy rainfall in a short amount of time, generally less than six (6) hours.

We also had flooding from the Ohio River, known as riverine flooding.  In Jeffersonville and Clarksville, several roads had to be closed due to the high river level.

Localized flooding issues can occur due to issues with drainage infrastructure.  Below, we learn a little bit about drainage.

Where does the water go?

There are two places that stormwater flows:

  • Combined Sewers:  The stormwater and sanitary sewer water goes to the wastewater plant.  During major storm events, flow in the pipes may be diverted directly to the Ohio River so the wastewater plant does not get overloaded;
  • Separate Storm Sewers: The stormwater drainage system is not connected to the sanitary sewer system.  Precipitation flows directly to the nearest stream, which eventually ends up in the Ohio River.
There is a storm sewer pipe next to the telephone pole. It takes water from the street and backyards of the neighborhood.

There is a concrete storm sewer pipe next to the telephone pole (you can see the top of it coming out of the grass). It takes water from the street and backyards of the neighborhood.  Also, notice that this creek has been channelized.

What are the parts of a drainage system?

The simple story is that there are ditches, pipes, and catch basins (inlets) that carry water away from our homes and the street.  Think of a puzzle…there are lots of pieces and they all have to be properly in place.  As mentioned above, in the separate storm sewer system, water is carried to the nearest waterway (usually a small stream).  That excess water has to go somewhere!

Ditches are typically vegetated, rock, or concrete.  They can also be combination of those materials, such as the bottom 2 ft. being concrete with the sides being grass.

This ditch is grass only and must be mowed so it does not have trees etc. grow in it.

This ditch is grass only and must be mowed so it does not have trees etc. grow in it.  Trees and shrubs will destroy the ditch.

A ditch that has large rock (rip rap) to protect it from eroding.

A ditch that has large rock (rip rap) to protect it from eroding.

Pipes are usually concrete, PVC, High Density Polyethylene Pipe (HDPE; fancy word for tough plastic).  There are numerous pipe options.

Here is HDPE drainage pipe being installed.

Here is HDPE drainage pipe being installed.  The small rock ‘beds’ the pipe, which provides stability and strength.

On the right side, you can see the galvanized metal drainage pipe. If you look closely, you can see the rust (brown color). It got replaced!

On the right side, you can see the galvanized metal drainage pipe. If you look closely, you can see the rust (brown color). It got replaced!

Catch basins and inlets are where the water flow into from the road or yard to get into the drainage system.

The catch basin under the mailbox takes water off the road.

The catch basin under the mailbox takes water off the road.

This catch basin is in a yard and takes water from a ditch.

This inlet is in a yard (next to a driveway) and takes water from a ditch.

Stuff fails

So now you know some of the parts to a drainage system.  But how do they fail?  Several reasons:

  • Tree limbs, yard waste, leaves, etc. all clog ditches and cover up inlets…classic blockages;
  • The drainage system gets old and needs replaced.  Pipes rust, give up on life, and collapse;
  •  Rainfall events today are becoming more frequent, with higher amounts of precipitation falling.  Some drainage pipes have been in the ground for 50+ years and were not designed to handle this much rain.  They are undersized for today’s wet weather.

The flood finale

The house on the hill is a great spot to build if you want to limit your flooding potential.  However, there can still be a danger of flash flooding and / or a problem with the drainage system in your area.  In our communities, we work hard to fix the drainage system issues that we are aware of.  If you know of problems in your area, call us and we will come take a look.  We may not be aware of the issue.  It only takes one puzzle piece of the drainage system to have a problem, which can cause a flood.

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