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National Lake Assessment - 2012
National Lake Assessment (NLA): This was EPA's second snapshot of the condition of the nation's lakes was completed this past summer. Oklahoma has 32 of the over 900 included lakes nationwide. The Lakes team wrapped up the field sampling component for the 2012 National Lakes Assessment in mid-September. The next phase of the project is lab analysis which will be conducted in 2013 by various laboratories across the country, followed by the reporting process in 2014. For more information visit EPA’s NLA web page or thier fact sheet.
What is NLA?
What were the goals of NLA?
What was measured?
Human Use Indicators
A comparison of the 2007 and 2012 survey measurements:
In 2007, the Oklahoma Water Resources Board participated in the National Lakes Assessment by sampling thirty-five probabilistic sites. Headquarter 106 monies were leveraged with regional funds for eighteen additional sites allowing a state level survey. The bulk of the entire probabilistic survey included Beneficial Use Monitoring Program lakes (30/53). The Environmental Protection Agency provided many beneficial facets for participating in the survey. One of the key areas was building capacity for improving the monitoring program at the state level. Because the majority of lakes that were sampled by the probabilistic survey were BUMP lakes, the demonstration allowed for long-term BUMP monitoring data to be compared to the data from the survey, an inventory of the lakes within the twelve ecoregions of the state, and biological parameters and data to be added to the assessment of the state's waters. Oklahoma is looking to the future with the possibility of using the data for further development of nutrient and biological criteria, re-evaluating the water quality standards for these waters and incorporating new parameters into the established monitoring program.
Concurrently, a similar statewide survey was conducted, the Oklahoma State Lakes Survey. This probability based survey collected samples representing lakes, ponds and reservoirs 10 acres in Oklahoma. The Oklahoma State Lakes Survey (OSLS) represents the first time 100 percent of the state’s lakes have been assessed in any fashion. The Oklahoma Water Resources Board (OWRB) estimates the bodies of water in this category at approximately 3,056 lakes, ponds and reservoirs within the State of Oklahoma, with a cumulative surface area of approximately 671,777 acres. The OSLS was patterned after and executed in conjunction with U.S. Environmental Protection Agency’s (EPA) National Lake Assessment (NLA). The EPA added 18 additional lakes to the 35 Oklahoma lakes already in the national draw. This made for a statistically robust state level probabilistic survey while following NLA methods with few exceptions. Because of the expansion of the probabilistic survey to more than 50 lakes, water quality status could now be inferred within at least a 95 percent confidence (complete report...).
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Page last updated: May 10, 2013