Flooding From Excessive Rain Downstream From Earth Dams

The Daily Republic in South Dakota published an article that talks about an earthen dam that recently failed because of a nine-inch rainfall last 29th of July 2010. The heavy rainfall overwhelmed the dam’s capacity causing it to fail.

No injury was reported on the said event. The said damn was built in 1935, as were a number of them during the Work Programs after the Great Depression. In 2007, it was inspected by a Department of Game, Fish and Parks Engineer and he noted that they “were satisfied with the condition of the dam” during that time. It was then again inspected in 2008 and it was said that the dam breach “was caused by an extraordinary natural event and not by any structural weakness in the dam.” (Photograph by Laura Wehde/The Daily Republic).

Earth dams are almost too numerous to count around the country. In fact, you might just be living near one without you knowing it. A great percentage of these dams were built over 70 years ago and, in many cases, the owners today were not the same ones when they were initially built. For this reason, maintenance and inspection of these dams became less popular.

FEMA estimates “there are over 80,000 dams in the United States”, and that approximately “one third of these pose a ‘high’ or ‘significant’ hazard to life and property if failure occurs.”

The South Fork dam, the country’s worst dam failure disaster in May of 1889, took over 2200 lives and almost half of which were under 20 years old. This incident happened in the town of Johnstown, PA, thus it was known as the “Johnstown Flood”. A 37-foot high wall of water hit Johnstown, located 9 miles downstream from the dam. It almost destroyed the entire city as 1600 homes and 280 businesses was flushed away.

In March 1928, the St. Francis Dam in California also failed. This caused a legislation to be enacted in and around the said state. This, and other later legislation led to life-saving advance warning when the Baldwin Hills dam near Los Angeles, California failed on December 14, 1963. Because of the advance warning which enabled the evacuation of approximately 16,500, the casualties from dam failures has significantly decreased to 5 individuals

Even though there have been far less loss of lives in the United States from dam failures since the 1970’s,The Association of State Dam Safety Officials reports that…

there were 132 dam failures and 434 “incidents” between January 2005 and January 2009.

Of course, It should be noted that the failure of the earthen levees near New Orleans, LA during and after Hurricane Katrina are purported to be responsible for killing more than 1000 people.

Failure in The KaLoko Dam on the Island of Kauai, Hawaii in March 2006 has resulted to the death of 7 people. Two years after the said incident, developer James Pfluegar was indicated for manslaughter and reckless endangerment in relation to the dam failure. The incident had caused the country of Kauai and the State of Hawaii to pay out over $9 Million in of lawsuits after the failure.

Cause of Dam Failures

Heavy rains cause overtopping, which is by far the most common cause of dam failures. Dam spillways and structures are typically not designed for more than a 1-percent chance (aka 100-year) storm event. When a rain event exceeds this, the water starts to travel outside of the control spillway. This causes erosion of the soil on the dam from the excessive amount of water traveling over it. It is also possible for overtopping to occur from smaller rain events because of debris blockage of the outlet structure or spillways or because of settlement of the dam crest.

Foundation defects, including settlement and slope instability, cause about 30% of all dam failures.

Seepage or Piping causes the remaining 20% of the U.S. dam failures. Piping is the internal erosion caused by seepage under and through the dam. This usually happens around structures such as pipes through the dam and spillways. Seepage can also be caused by animals, like beavers, muskrats, groundhogs, and other rodents, burrowing in the dam, by roots of trees growing on the dam, and through cracks in the dam.  All earth dams have seepage resulting from water permeating slowly through the dam and its foundation. But this seepage must be controlled or it will progressively erode soil from the embankment or its foundation, resulting in rapid failure of the dam.

What Should You Do To Protect Home?

Since the failure of a dam causes flood, your best option is to avoid building in a flood zone, unless you elevate and reinforce your home. Have your area surveyed and investigated for dam failure and flood determination so you’ll know if your dream house is safe to be constructed in that certain area.

Do you live downstream from a dam? Is the dam a high-hazard or significant-hazard potential dam? To find out, contact your state or county emergency management agency and/or visit the National Inventory of Dams. There are around 2,228 dams on the National Inventory in Alabama. And among those, 636 are listed as high or significant hazard potential dams.

If you live downstream from one of these dams, find out who owns and regulates the dam. This information should also be available from the National Inventory of Dams.

Next, find out if there is an Emergency Action Plan in place. Again, consult your state or county emergency management agency. (Alabama Emergency Management Agency)

Strangely enough, Alabama is the only state in the United States that has not passed dam safety legislation.

If you want help with investigating a piece of property you are considering purchasing or of one you already purchased, please call Talladega Land Surveying today at  256-854-9503 or fill out a contact form request.

How To Find Your Home On FEMA’s Flood Insurance Rate Maps

FEMA

FEMA‘s Flood Insurance Rate Maps (FIRMs) are provided after a flood risk assessment has been completed or updated for a community.  This study is known as a Flood Insurance Study.  The FIRM gives you the Base Flood Elevations (BFEs) and insurance risk zones in addition to floodplain boundaries.  The FIRM may also show a delineation of the regulatory floodway.

FEMA

Once the “insurance risk zone”  (commonly referred to as the flood zone) is determined, actuarial rates, based on these risk zones, are then applied for newly constructed, substantially approved, and substantially damaged buildings.  FEMA uses these rates to determine the insurance rate you will pay for flood insurance

FEMA discontinued the production and distribution of paper maps in 2009 as part of its Digital Vision Initiative. This affected all the Maps, boundary information, and study reports. However, clients can still view the products for free through their website or buy them in digital format.

To view these maps online, go toFEMA’s Map Service Centerand key in your address (hi-lited area shown here) search for your home.  This will prompt you to then select the map that covers your area.  The Flood Maps are somewhat cumbersome to use online. It is best to go through the tutorial on the bottom right of the address search page for an easier and more effective use of the GIS map.

Call Talladega Land Surveying at  256-854-9503 or  contact us if you need help with this process or if you discover you are near a flood zone and need an elevation survey completed.  We are here to help you minimize your flooding risk.

Estimate The Costs Of Flood Damage To Your Home

The tool below allows you to calculate the costs of flooding. Select a home size that approximates yours and then slide the blue button up or down for the expected depth of flooding.

Call Talladega Land Surveying TODAY for a free flood risk assessment of your home. We will review the flood maps in your area and advise whether we recommend a flood survey. CALL US TODAY at  256-854-9503 or fill out a contact form request. We Give You Peace of Mind.

What You Need to Know About Land Surveying

Land SurveyingLand surveying is the art and science of accurately measuring parcels of land. Measurements such as dimensions, lengths, boundary lines, including structures within the area are all precisely determined through a land survey.

These measurements are used to establish land maps, boundaries for ownership or for governmental purposes. It is a detailed study of every physical and cultural property of the land, whether above or beneath it, to illustrate it in usable form.

Data is gathered through observations, research, field measurements, and data analysis for establishing property boundaries. Records from previous surveys and government records will strengthen the reports made after the survey.

A land survey is classified according to the purpose or why the survey is being performed. Some of the common types of land survey are boundary surveys, topographic surveys, partition or subdivision surveys, flood elevation survey, property line adjustment survey, and extended title insurance coverage survey.

Other services such as mapping, construction layout surveys, judicial surveys, registered land surveys are all part of land surveying. It is an essential element in every development of the environment especially in the fields of construction, transport, communication, mapping, and most especially in the definition of legal boundaries for ownership.

The key component in the field of land surveying is the land surveyor. A land surveyor is a person that takes charge of every activity that transpires during a land survey. It is the surveyor who makes the research and data gathering and even interpretation and analysis of all data wherein translation of all data gathered is crucial and should be checked, attested, and sworn in the law to be true and correct.

It is important then for you to choose a land surveyor with the highest degree of expertise and who can assume responsibility for the complex tasks at hand. It should be emphasized that only a surveyor who has knowledge of the elements of geometry, trigonometry, engineering, mathematics, physics, and the law are expected to have the best land survey outcomes.

Land surveying is a profession as old as the Egyptian times yet its importance to the human race still lives on. It is the best method to settle disputes over land ownership, it gives a clear picture of what buildings are suited to be constructed in a given land area, and it’s a convenient way to determine the exact dimensions of real estate to be purchased or sold.

Land Surveying

Optimum potential of the land you own can only be defined once you have a land survey.

Whether you are planning to put it on the market, or should you want to use it for commercial purposes, a land survey must back you up if ever questions regarding everything about the land arise. Land surveying will provide a sense of security and peace of mind to every land owner and even to the future buyers.

Land surveying will always be an integral part in protecting real estate and upholding of laws governing the utilization and distribution of your land assets.

Call Talladega Land Surveying today at 256-854-9503 or fill out a request for more information concerning your land surveying needs.

Things You Need to Know Before Building a House

 

Land SurveyingIt is a very good idea to build your home because you will be able to get exactly what you want instead of when you buy. Of course, you may need to add some things or you may not know what you are getting yourself into. The following are some of the things that you might want know when planning to build your house.

Choosing the right builder is a big decision since this is one of the most important investments that you will ever make. Interview all possible house contractors and hire the one that understands what you want and how you want things to be done.

When interviewing the contractors make sure that you ask all the possible questions that will help you in your decision; how long have they been building houses, also if you can view any of their work, and to see references. It is also crucial to pick house plans that would lead to a good home now and in the future. This is something that your contractor should be able to help you with and they may call on the services of an architect.

Before planning and finalizing your design try to consider these things; budget, home size, home location, wall finishing, special design features, height of ceilings, stories, fixtures, outside finishing, and your time frame for completion.

If you are having a difficult time picking any of these items you should make an appointment with your contractor and/or architect. They are sure to assist in choosing right down to every tiny detail. When they have done their job of guiding you, you will have spent a lot of time because this is a detailed process which shouldn’t be short-changed. This is the reason why your choice of a builder is important.

If your builder isn’t able to advise you on home location they should refer you to a real estate agent. A real estate agent should be experienced in advising on home values in certain areas, what school districts are preferred, traffic congestion issues, your financing options, among other things.

Another stop you should make is to see a land surveyor. Land surveyors are trained and experienced in identifying features of the land that might have an impact on your new home. Some of these features are flood zones, property line encroachments from neighbors, lot dimensions, and building setbacks. Land surveyors are measurement experts. And, since your home is your most valuable asset, a survey of your land should be one of your first steps in any new construction.

Call Talladega Land Surveying today at 256-854-9503  or fill out a contact form request for more information concerning your land surveying needs.