Tag Archive for: elevation

Easy Way to Find the Elevation of a Home and the Slopes Around It

Ever wonder how high your slab is compared to the elevation of your street? Or where water is likely to collect in a neighborhood? The US Geological Survey (USGS) has given us a quick and easy way to lean more about elevation.

While the site says the elevations are not as good as a survey’s, I found the elevation for my house to be within inches. This is not something to take to the bank, but if you’re trying to:

  • Screen several properties for purchase
  • Figure out why some people in a neighborhood flooded and others didn’t
  • Understand where floodwaters might collect

…this is a good place to start.

To Find Elevation

  • Go to this U.S. Geological Survey website called the National Map Viewer.
  • Enter an address or just zoom into the area of interest.
  • Select a base map by clicking on the icon with the four squares that form another square. Different base maps allow different degrees of zooming and show various features such as streets, water features, topography, etc., so experiment.
  • Above the map area, click on the icon that shows an XY.
  • A box will pop up on the right side of the screen. Within it, click “Activate.”
  • Click on the map location or locations that interest you.
  • An info box will pop up that shows the location and elevation at the blue dot(s) where you clicked.
  • To erase the points you selected, click “Deactivate.”
Elevations for Riverwood and East End Park Parking Lot

You can click as many different points as you want. A list of ALL the places you clicked with their elevations will show up in the right hand box.

In the example shown above, you can see that Riverwood Middle School at the intersection of High Valley and Kingwood Drive is at 65.03 feet. You can also see that the entry for East End Park is at 53.68 feet – more than 11 feet lower just a couple blocks away.

How High Is A Home Above Street Level?

This question is crucial if you want to avoid street flooding during high intensity rainfalls that overwhelm the capacity of storm drains and force water to back up in the streets.

  • Switch to the base map called Streets (if you were in something else)
  • Zoom in on the area of interest or enter an address.
  • Again select the XY tool.
  • Click on the home that interests you to see the elevation of the slab.
  • Click on the street in front of it.
Note 3 foot elevation difference between slab and house in Streets Basemap.

Three feet is a pretty good difference. But another home in the same neighborhood has a 4.5 foot difference!

This home sits 4.5 feet above the street.

Click around in different neighborhoods, especially those that flooded. On a block that flooded badly in Elm Grove, one home escaped. It was also 4.5 feet above street level. Others around it ranged from 1 to 3 feet above street level.

When buying a home, elevation above street level can be a valuable consideration.

Streets are usually considered part of the flood retention system. Developers size storm drains to hold a 1- or 2-year rain. Everything beyond that up to a 100-year rain backs up into the street until it can be safely released into drainage ditches. If you aren’t high enough…

Slope Within Neighborhoods

USGS offers another useful tool called elevation profiling. To the left of the XY tool, click the tool called Profile.

  • A box will pop up on the right of the screen. To activate this tool, click on the ruler icon in the box.
  • Define a path with two or more points.
  • In the example below, I followed the curves of a street by clicking multiple times.
  • When you get to the end of the area of interest, DOUBLE click.
  • Double clicking changes the tab in the right hand box and starts compiling an elevation profile result.
  • Give the site a few seconds to compile and display the profile.

When this profile popped up, I saw that this street had six feet of slope from the west end of the block to a low point in the middle and then rose back up three feet to the school on the right.

Example of Elevation Profile Tool. Note the U-shaped profile in blue and brown on the right.

It’s common practice to slope streets; developers must to ensure that water drains to storm sewers. But when the rain comes down so fast that the storm drains can’t handle it, guess where the rain will collect. I’m not sure I would want to buy the house at the bottom of the bowl. (At least not without a discount to compensate for the risk.)

Powerful Tools at Your Fingertips

USGS has given us a fascinating tool kit. I have just begun to explore the power of this site.

Several people in Kingwood’s Woodstream Village approached me about some flooding on their street. Using the tools on this site, I quickly developed a theory that accounted for all the eyewitness stories.

Have fun exploring this fascinating tool.

Posted by Bob Rehak on 8/1/2020 with thanks to Laura Norton

1068 Days since Hurricane Harvey and 316 since Imelda

City To Host Meeting Tuesday, 6:30, At Kingwood Community Center for Homeowners Who Suffered Repetitive Flood Damage

This post is for all those unfortunate people who have suffered repetitive flood damage. Learn how you may qualify for federal assistance to elevate your home.

On Tuesday, October 15, at 6:30 p.m., the City of Houston will host a meeting about mitigation grant assistance for repetitive flood-damaged properties at the Kingwood Community Center.

The community center is at 4102 Rustic Woods, Kingwood, TX 77345 on the corner of West Lake Houston Parkway, near the Kingwood Park ‘N Ride.

Properties may qualify for Federal Emergency Management Assistance (FEMA) funding for structure elevation.

Many families in Elm Grove who flooded in May also flooded in September and should explore the options in this meeting. Regardless of where you live in the City, if your home has flooded at least twice, you may be eligible to have your home elevated.

Homeowners can speak with the City regarding options. To quality, property owners must:

  • Hold a National Flood Insurance Program (NFIP) policy.
  • Reside within Houston city limits.
  • Have flooded at least twice.

Below is more information.

Information about Tuesday’s meeting
Info About the Program.

Please submit the voluntary interest form available here

Thanks to Houston City Council Member Dave Martin for setting this up.

Posted by Bob Rehak on 10/13/2019

775 Days since Hurricane Harvey and 24 since Imelda

Where do you live relative to official flood plains?

During Harvey tens of thousands of people in the Houston area outside of 100-year and 500-year flood plains flooded. Do you really know your home’s location relative to official flood plains? It could be important during lesser floods and affect the cost of flood insurance.

This FEMA web site shows interactive flood plain maps that can give you a wealth of information about the risk to your property.

Feature-rich, Interactive Flood-Plain Map by FEMA

Access FEMA’s Flood Zone map for this area by going to this web page: http://maps.riskmap6.com/TX/Harris/

Then follow these steps:

  1. When you get to the entry page, agree to terms and conditions
  2. Type in  your address to get a detailed view of risk for yourself and your neighborhood. Or you can also type in something more general, such as Kingwood TX, to see the contour of flood plains in the entire community.
  3. On the left-hand panel, check both boxes under “Effective Flood Insurance Rate Map.”
  4. The legend is on the right. Some explanations:
    1. Anything in solid purple is in the FLOODWAY. Expect frequent flooding and major damage.
    2. Anything under the fuchsia diagonal stripes is in the 100-year plain. People there have a 1% probability of flooding every year – and a 26% chance of flooding during the life of a 30-year mortgage.
    3. Anything under grey diagonal stripes is in the 500-year flood plain. People there have a 0.2% probability of flooding every year – and a 5.8% chance of flooding during the life of a 30-year mortgage.
    4. Properties outside those zones are in an area of overall lower risk. Lower-cost, preferred-rate, flood insurance policies (known as Preferred Risk Policies) are often an option in these areas. See your local insurance agent or visit floodsmart.gov for more information.
  5. If you entered your specific address, click the info button above the map, then click the star on your property to learn more about your risk. After the box pops up, you can click “View Detailed Flood Report” for even more information.
  6. You can hide both the legend and check box panels by clicking on the >> double arrows at the top of each panel.
  7. Zoom and move about, as you would Google Maps.
  8. Use the measuring tool above the map to check your distance from flood zones and hazards such as streams, ditches and rivers.

Guide to Terminology

If you need help interpreting all the acronyms and technical language in the check boxes and legend, consult this PDF: How to read a FEMA Map

The PDF above is definitely worth a read. It explains the “language” of flooding and flood insurance. It also explains how to protest a designation if you think the map has misclassified your property, for instance, if your slab has been elevated relative to the average level around you.

Experiment with the different tools and views in the map. Zoom out to see the risk in surrounding areas. The interactive exploration is fascinating.

Regardless of how far you are from flood plains or how high you are above them, if you live in Harris County, seriously consider flood insurance. During Harvey, more homes flooded outside the 500-year flood plain than inside.

A Less Powerful, but Easier-to-Understand Alternative

Harris County Flood Control offers a web site similar to FEMA’s; it has fewer options and less information, but is easier to understand and navigate. It’s actually called a “flood education mapping tool.” See: http://www.harriscountyfemt.org/Index.aspx.

The flood education mapping tool from Harris County Flood Control District has fewer options but is easier to understand.

How to Find the Elevation of Your Home

If you don’t already know the elevation of your home from surveys, deeds or insurance docs, try this web site: https://elevationmap.net/.

My thanks to Paul Margaritis, a long-time Kingwood resident. Paul forwarded this information to RefuceFlooding.com.

Posted 5/29/2018 by Bob Rehak

273 days since Hurricane Harvey