Much of the infrastructure in the United States is aged and in need of renovation and replacement. Dams, in particular, are deteriorating, some of them to dangerous levels. Much of the 87,000 dams in this country are nearing 50 years old and need our attention.
To completely modernize the US infrastructure (roads, bridges, dams, etc.) in the next decade the federal government needs to invest upwards of $3.3 trillion in projects. That number comes from an American Society of Civil Engineers (ASCE) report called Failure to Act – Closing the Infrastructure Investment Game for America’s Economic Future.
Most of the aging dams have lost the ability to effectively control the water with which they were originally designed. Shifting weather patterns can bring heavier rain and storms to dams not built to handle the new amount of water. In addition, urban developments have been constructed putting formerly low risk, rural dams into a hazardous category now.
The good news is the US Senate passes the Water Resources Development Act (WRDA) of 2016. The bill, S.2848, authorizes the US Army Corps of Engineers to invest in flood control management and ecosystem restoration. It is not nearly enough given the overwhelming need, but it is a start.
“Many citizens think of dams as those which are impounding and storing water. They are unaware of the many ‘dry’ flood control dams and levees which aim to keep the public and property safe from rain related runoff and debris flows,” states Kevin L. Paul, Senior Engineer with Earth Systems Southwest. “We are thrilled to be able to perform further exploration and evaluations for the many dams structures in our area which have been constructed in the past and may be suspect in their stability. This is a direct benefit to public safety.”
For example, Earth Systems recently completed work on the award winning Eagle Canyon Dam in Cathedral City, CA (ASCE Los Angeles Section – Flood Management Project of the Year) and has just started work on the Woodcrest Dam located near Hermosa Drive and Washington Street in Riverside, CA. The Woodcrest Dam is alleged to be founded upon potentially liquefiable soils and has experienced some distress. So, considerable exploration, testing, and engineering analysis is required to adequately characterize the geologic and soil conditions within and around the dam.
“We are using a multi-phased approach with boring and CPT equipment, as well as geophysical techniques, laboratory testing, and analysis,” says Mr. Paul. “The aim is to quantify the threshold seismic loading and magnitude of deformation of the dam structure under various loading scenarios.” The goal is to meet the requirements of the Department of Safety of Dams (DSOD) in evaluating/reporting requirements for earthen water retention structures, as well as seepage and slope stability analyses with the Army Corp of Engineers.
According to the DSOD, “Much of the problem with analyzing embankments is our inability to representatively sample and test earth materials, understand the behavior of observed performance, and conceptualize and model failure modes for the multitude of different embankment sections. The purpose of exploration and testing is to determine the physical characteristics of the foundation and embankment and their engineering properties. An understanding of the site geology is essential to gain insight for developing exploration and testing programs that will aid in the construction of analytical models. A geologist can assist the engineering in making judgments on the extent, homogeneity or lack thereof in a foundation.”
Modern infrastructure is critical to our nation’s prosperity, health, and welfare. “Most Americans don’t completely understand just how sorely our dams and water infrastructure need our attention and investment,” adds Mr. Paul. “However, we are happy to do our part.”