Re: Cattle impacts and water quality
Posted: Mon May 24, 2010 9:50 pm
This will surprise no one, but releveant to the topic, this just in from the Central Sierra Environmental Resource Center (my point is only to argue that all parties should seek to abide within the laws. Grazing is allowed within limits as set by objective impacts.) Material below from CSERC newsletter:
CSERC Study Shows That Livestock Presence Can Affect The Water Quality Of Streams In The Stanislaus National Forest
In an intensive water study done at four forest streams in the Stanislaus National Forest, water quality samples collected last summer by CSERC staff and tested by an independent laboratory showed high levels of contamination once livestock were present alongside the streams. The detailed CSERC water study report has now been released for scientific review and public consideration.
Background
For the past 15 years, CSERC staff has carefully monitored livestock impacts to meadows and riparian areas within the Stanislaus National Forest. Under the leadership of the Center's biologists, CSERC staff has measured grass heights of key species at agency-specified locations before cows begin grazing in forest meadows. Then the staff measures those same areas again near the end of the grazing season to compare measurements. Using the Forest Service's own protocols, CSERC has found that most years there are many areas where livestock grazing violates the agency's clearly spelled out standards and guidelines. Utilization of meadow grasses by livestock is either beyond the limits or stubble height standards are not met. Put simply, that means the meadows are overgrazed.
The result for the ecosystem is that there is often little habitat value left for wildlife. Streambanks are frequently denuded or trampled. Sediment erodes into streams.
But despite the obvious resource impacts at heavily grazed meadows and stream areas, the question of water quality impacts was far less certain. Even where cows trampled a streambank or significantly over-grazed the grass in a meadow, there was no proof that water quality was actually being affected.
Research Approach
To try to find science-based answers, CSERC planned a study project last summer that was consistent with State Water Board protocols and depended upon independent laboratory testing of water samples. Lindsey (CSERC biologist) started the effort by spending weeks developing a carefully developed Quality Assurance Project Plan that would spell out exactly how the water study would be done. Then she and CSERC’s director John began visiting four meadows where monitoring from previous years showed that cows grazed fairly early in the summer season.
The Center took multiple water quality samples in the weeks before cows arrived at the four meadows. Once cows were present in the general area, CSERC continued to take water samples. Following the established protocol, all of the samples were carefully collected, kept out of sunlight on ice in a cooler, and turned over to the independent laboratory in less than six hours.
Results
The results were startling. Prior to the time that cows arrived at meadows alongside the forest streams, the water quality was generally good. State water quality standards for recreational contact objectives were met. But soon after cows arrived, the level of bacterial contamination in the water significantly increased. Testing of samples showed that the water was contaminated by excessive levels of total coliform, fecal coliform, and E. coli. The fecal coliform contamination was proven to be at levels that exceeded Basin Plan levels for recreational contact, let alone for drinking.
In the past, when CSERC complained to Stanislaus Forest officials that streams were being contaminated at levels unsafe for campers, hikers, backpackers, fishermen, and other visitors to drink, the Forest Service firmly dismissed any problem. In writing, the Forest Service took the position that forest visitors should always be treating stream and lake water, so it didn't pose a health risk for stream water to be unsafe for drinking straight from a stream. CSERC responded to the Forest Service that many people who visit the Forest don't bring water purifiers, and low-income visitors may not be able to afford the cost of the expensive filters.
The CSERC study and last summer's water sampling showed that State standards were violated, whether or not people drank water from the streams. Even using only the recreational contact standard in the Basin Plan, there were many significant water quality violations at the four streams that were the focus of the CSERC study.
In addition, Lindsey and her support team sampled water in another area of the Forest by collecting two samples from a spring. The first sample was collected downstream from the source, below where livestock use was highly visible. A second sample was then collected above the disturbance from the source of the spring. The water at the spring was nearly pure, but just downstream where cows were affecting the stream zone, the water contamination exceeded Basin Plan standards.
As a control, CSERC collected multiple water samples from a stream below an ungrazed meadow during the grazing season. At the ungrazed stream area, water quality remained high throughout the entire sampling period. Any wildlife contamination that occurred at the control stream never contributed to any level of fecal coliform or E. coli that was close to a health threshold of concern. The only stream in the study that stayed at safe levels throughout the sampling period was in the ungrazed stream area.
Despite the clear evidence that the four base streams in the water study had water quality violations of State standards after livestock arrived, CSERC did not just take that data and immediately publicize vocal concerns. Instead, Lindsey studiously worked throughout the winter and spring to carefully organize the data, provide graphs and tables, and coordinate with a statistical analyst to scrutinize the study results. Finally, in May of this year, CSERC felt ready to finalize the Water Study report and release the findings to the State Water Board and the U.S. Forest Service.
Implications of results
Interest groups that support the continuation of status quo grazing practices in the Sierra Nevada region may discount the study or suggest that stream contamination is not widespread. CSERC notes, however, that the same "best management practices" that the Forest Service applies to livestock grazing in the four stream locations of the CSERC water study are identical to management practices that the agency applies to livestock grazing elsewhere throughout the North Coast and Sierra Nevada region. Since every stream sampled during the 2009 CSERC study showed violations of State water standards, sampling of other streams in the national forests of the region appears to be justified to assess the potential of contamination by livestock elsewhere, as well.
One take-away message was clear from the CSERC water study. DO NOT DRINK UNTREATED WATER FROM ANY FOREST STREAM WHERE LIVESTOCK CONTAMINATION IS POSSIBLE. Even where stream water was not obviously muddy or full of algae, the visually clear water at CSERC study sites was still polluted at unsafe levels once cows had been present.
CSERC director John Buckley stressed, "We were surprised that even clean-looking stream water was so contaminated. We urge all of our members and other forest visitors to always treat water or bring safe water with you when you come to the mountains, if possible. It simply isn't worth the risk to drink from streams that may be polluted."
CSERC Study Shows That Livestock Presence Can Affect The Water Quality Of Streams In The Stanislaus National Forest
In an intensive water study done at four forest streams in the Stanislaus National Forest, water quality samples collected last summer by CSERC staff and tested by an independent laboratory showed high levels of contamination once livestock were present alongside the streams. The detailed CSERC water study report has now been released for scientific review and public consideration.
Background
For the past 15 years, CSERC staff has carefully monitored livestock impacts to meadows and riparian areas within the Stanislaus National Forest. Under the leadership of the Center's biologists, CSERC staff has measured grass heights of key species at agency-specified locations before cows begin grazing in forest meadows. Then the staff measures those same areas again near the end of the grazing season to compare measurements. Using the Forest Service's own protocols, CSERC has found that most years there are many areas where livestock grazing violates the agency's clearly spelled out standards and guidelines. Utilization of meadow grasses by livestock is either beyond the limits or stubble height standards are not met. Put simply, that means the meadows are overgrazed.
The result for the ecosystem is that there is often little habitat value left for wildlife. Streambanks are frequently denuded or trampled. Sediment erodes into streams.
But despite the obvious resource impacts at heavily grazed meadows and stream areas, the question of water quality impacts was far less certain. Even where cows trampled a streambank or significantly over-grazed the grass in a meadow, there was no proof that water quality was actually being affected.
Research Approach
To try to find science-based answers, CSERC planned a study project last summer that was consistent with State Water Board protocols and depended upon independent laboratory testing of water samples. Lindsey (CSERC biologist) started the effort by spending weeks developing a carefully developed Quality Assurance Project Plan that would spell out exactly how the water study would be done. Then she and CSERC’s director John began visiting four meadows where monitoring from previous years showed that cows grazed fairly early in the summer season.
The Center took multiple water quality samples in the weeks before cows arrived at the four meadows. Once cows were present in the general area, CSERC continued to take water samples. Following the established protocol, all of the samples were carefully collected, kept out of sunlight on ice in a cooler, and turned over to the independent laboratory in less than six hours.
Results
The results were startling. Prior to the time that cows arrived at meadows alongside the forest streams, the water quality was generally good. State water quality standards for recreational contact objectives were met. But soon after cows arrived, the level of bacterial contamination in the water significantly increased. Testing of samples showed that the water was contaminated by excessive levels of total coliform, fecal coliform, and E. coli. The fecal coliform contamination was proven to be at levels that exceeded Basin Plan levels for recreational contact, let alone for drinking.
In the past, when CSERC complained to Stanislaus Forest officials that streams were being contaminated at levels unsafe for campers, hikers, backpackers, fishermen, and other visitors to drink, the Forest Service firmly dismissed any problem. In writing, the Forest Service took the position that forest visitors should always be treating stream and lake water, so it didn't pose a health risk for stream water to be unsafe for drinking straight from a stream. CSERC responded to the Forest Service that many people who visit the Forest don't bring water purifiers, and low-income visitors may not be able to afford the cost of the expensive filters.
The CSERC study and last summer's water sampling showed that State standards were violated, whether or not people drank water from the streams. Even using only the recreational contact standard in the Basin Plan, there were many significant water quality violations at the four streams that were the focus of the CSERC study.
In addition, Lindsey and her support team sampled water in another area of the Forest by collecting two samples from a spring. The first sample was collected downstream from the source, below where livestock use was highly visible. A second sample was then collected above the disturbance from the source of the spring. The water at the spring was nearly pure, but just downstream where cows were affecting the stream zone, the water contamination exceeded Basin Plan standards.
As a control, CSERC collected multiple water samples from a stream below an ungrazed meadow during the grazing season. At the ungrazed stream area, water quality remained high throughout the entire sampling period. Any wildlife contamination that occurred at the control stream never contributed to any level of fecal coliform or E. coli that was close to a health threshold of concern. The only stream in the study that stayed at safe levels throughout the sampling period was in the ungrazed stream area.
Despite the clear evidence that the four base streams in the water study had water quality violations of State standards after livestock arrived, CSERC did not just take that data and immediately publicize vocal concerns. Instead, Lindsey studiously worked throughout the winter and spring to carefully organize the data, provide graphs and tables, and coordinate with a statistical analyst to scrutinize the study results. Finally, in May of this year, CSERC felt ready to finalize the Water Study report and release the findings to the State Water Board and the U.S. Forest Service.
Implications of results
Interest groups that support the continuation of status quo grazing practices in the Sierra Nevada region may discount the study or suggest that stream contamination is not widespread. CSERC notes, however, that the same "best management practices" that the Forest Service applies to livestock grazing in the four stream locations of the CSERC water study are identical to management practices that the agency applies to livestock grazing elsewhere throughout the North Coast and Sierra Nevada region. Since every stream sampled during the 2009 CSERC study showed violations of State water standards, sampling of other streams in the national forests of the region appears to be justified to assess the potential of contamination by livestock elsewhere, as well.
One take-away message was clear from the CSERC water study. DO NOT DRINK UNTREATED WATER FROM ANY FOREST STREAM WHERE LIVESTOCK CONTAMINATION IS POSSIBLE. Even where stream water was not obviously muddy or full of algae, the visually clear water at CSERC study sites was still polluted at unsafe levels once cows had been present.
CSERC director John Buckley stressed, "We were surprised that even clean-looking stream water was so contaminated. We urge all of our members and other forest visitors to always treat water or bring safe water with you when you come to the mountains, if possible. It simply isn't worth the risk to drink from streams that may be polluted."