Livestock Grazing and Water Quality and Quantity
How drastically does livestock grazing degrade water quality and quantity?
Public lands in general and national forest lands in particular tend to be located at the headwaters of western watersheds. Those headwaters are typically dominated by extensive meadow systems, including wet, moist and dry meadow areas. Most Americans are surprised when they learn that those western headwaters are grazed each and every year by non-native, private livestock, typically cattle but also sheep, goats and even llamas.
The headwaters of western streams have an out-sized impact on water quality and water supply. Healthy meadow systems produce clean, cool water which sustains cold water fisheries and recharges groundwater downstream. These watersheds also provide the water supply on which western farms, ranches and communities depend. In fact, protecting water supplies is one of two reasons national forest lands were set aside, that is, to protect and sustain “favorable conditions of flow” in the region’s streams.
In addition to national forests, federal lands grazed by private livestock include public domain lands managed by the Bureau of Land Management and important national wildlife refuges. Public Domain Lands are not always located at the headwaters of western streams. They, as well as some national forest and most wildlife refuge land, are sometimes located at lower elevation in our watersheds. But wherever they are located, public lands and how they are managed impacts surface flows, groundwater and water supplies.
What are the impacts of that public land grazing on water quality, water supply, streamflow and wildlife habitat? And how do the benefits of meat production compare to the costs in terms of impacts to water supply, water quality and streamflow?
Federal lands contribute about 2-3% of US meat production. Even when livestock grazing is well managed (which is rarely the case on federal lands), there are water quality, wetland, meadow and riparian impacts. When grazing is poorly managed, the result is significant degradation. Research conducted within the Cascade-Siskiyou National Monument found that over 40% of the diet of grazing cattle consisted of wetland obligate plants. Other research, on public lands in Idaho and Oregon, found cattle were much more likely, as compared to deer, elk or even horses, to be photographed by game cameras placed within riparian areas.
This research confirms the findings of those who monitor public land grazing in the field: poorly managed cattle spend roughly half their time grazing within riparian areas and wetlands. The result, predictably, is degradation of water quality as streambanks are trampled and shade is removed, warming the water and filling it with sediment.
But water quality is not the only impact when cattle and other livestock are allowed to graze on public lands. Water supply and streamflows are also negatively impacted as wet meadows are trampled and compacted year after year by animals that can weigh over 1200 pounds.
The Forest Service’s own monitoring of meadow vegetation on national forest grazing allotments the length of California finds that there has been a long term loss of wetland obligate plants. That’s a strong indicator that wetlands are being destroyed as a result of grazing. Once degraded, meadows can take many years to recover their water storage capacity and they often require costly restoration interventions to facilitate the healing process.
Headwaters meadow trampling by non-native livestock damages the meadows’ water holding capacity, and results in larger flood flows and smaller base flows in streams below--which is why public land grazing is a significant factor in the dewatering plaguing many western streams. Lower base flows also means less water for domestic use and irrigation, damage or loss of fisheries, and degradation of stream ecosystems. To make matters worse, climate predictions indicate drastically reduced western snowpacks going forward. Less snowpack means reduced stream baseflows and reduced water supplies, magnifying the impact of headwaters livestock grazing.
Under these conditions we must question whether it makes sense to continue public land grazing. Given the urgency of the climate crisis, the Healthy Public Lands Project takes the position that the only appropriate response is to end this ecologically damaging, economically irresponsible practice. Public lands should be for public wildlife; the presence of non-native livestock has real costs for western communities.
Only 2-3% of the US beef supply comes from public lands. It does not make sense to damage water supplies, streamflows and fisheries to maintain this destructive use.
Riparian Meadow Response to Modern Conservation Grazing Management. Kristin M. Oles, Dave A. Weixelman, David F. Lile, Kenneth W. Tate, Laura K. Snell, Leslie M. Roche. Environmental Management (2017) 60:383–395. DOI 10.1007/s00267-017-0897-1)