Average Water Clarity Chart for 100 ABI Lakes
Water clarity (or visibility) is easily measured in lakes with a Secchi disc and can provide a quick determination of water quality. Higher visibility indicates a cleaner (and healthier) aquatic system. Cloudy conditions could indicate nutrient rich sediments entering the lake or excessive algal blooms due to nutrient availability. Clear conditions allow greater light penetration and the establishment of a deeper photic zone. The photic zone is the depth of active photosynthesis carried out by plants and algae. A byproduct of photosynthesis is dissolved oxygen, required for use by higher aquatic organisms, such as zooplankton and fish.
The graphs display the average visibility of 100 Allied Biological lakes throughout the growing season (April-September). For example: 6 lakes measured an average water clarity of 7 feet between April and September of 2010. (click thumbnail to view graph)
What Does This Mean?
Depending on where your lake falls on the graph you may want to consider measures to improve your water clarity and possibly implement a Water Quality Assessment & Monitoring Program. Regular monitoring can provide insight into causes of poor clarity, as well as other water quality problems. Browse through ABI’s Consulting Services to learn more about assessment and monitoring, or contact our office to discuss restoration solutions.
Average Dissolved Oxygen Chart for 100 ABI Lakes
Dissolved Oxygen (DO) is the measurement of the amount of oxygen freely available to aquatic biota in water. Several factors play a role in affecting the amount of dissolved oxygen in the water. These factors include temperature, low atmospheric pressure (such as higher altitude), the mineral content of the water, and water mixing (via wind, flow over rocks, or thermal upwelling). Warmer temperatures, low atmospheric pressure, and increased mineral content all conspire to decrease the solubility of oxygen in water. Lower temperatures and increased water mixing tend to increase the dissolved oxygen solubility in water. In addition, an over abundance of organic matter, such as dead algae or plants causes rapid aerobic bacteria growth. During this growth, bacteria consume oxygen during respiration, which can cause the water’s dissolved oxygen to decrease.
Dissolved oxygen has a wide range, from 0 ppm to 20 ppm. To support diverse aquatic biota, 5-6 mg/L is minimally required, but 9-10 ppm is an indicator of better overall water quality. A dissolved oxygen reading of below 4 ppm is stressful to most aquatic organisms, especially fish. Elevated dissolved oxygen readings, particularly those above 13.5 ppm observed during the growing season, are above the carrying capacity of the water and can be problematic. These high readings are generally created by the photosynthetic activity of an overabundance of algae. The danger comes at night when photosynthesis ceases and the dissolved oxygen could fall below 4 ppm.
The graphs display the average dissolved oxygen measured at 100 Allied Biological lakes throughout the growing season (April – September). For Example: 10 lakes had an average DO of 8.5 ppm between April and September of 2010. Bear in mind, not all lakes have oxygen sampled regularly, so a small number of samples taken in August, or in spring or fall, may skew your average. (click thumbnail to view graph)
What Does This Mean?
Depending on where your lake falls on the graph you may want to consider measures to improve your dissolved oxygen and possibly implement a Water Quality Assessment & Monitoring Program. Regular monitoring can provide insight into causes of poor dissolved oxygen, as well as other water quality problems. Browse through ABI’s Consulting Services to learn more about assessment and monitoring, or contact our office to discuss restoration solutions.
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