July 4, 2008
Catchment Care for Sustainability
By O'Riordan, Timothy
Agriculture is beginning to be counted in the sustainability stakes. Agricultural runoff poses one of the most significant threats to physical and chemical water quality in the United Kingdom, according to the U.K. Department for Environment, Food and Rural Affairs. And, as Juha Siikamaki makes clear in his article, "Climate Change and U.S. Agriculture: Examining the Connections" (page 36), the agricultural sector contributes a significant amount of greenhouse gas emissions-an amount that will likely grow in the face of critical food shortages and greater demand on crops for biofuels. Managing the two problems will prove difficult because agriculture is a mass of diffuse sources-fertilizers, pesticides, and mobilized soils running into watercourses farm by farm, and carbon dioxide, methane, and nitrous oxide emanating in small individual amounts but huge cumulative totals. What is more, one aspect of climate change is the increased likelihood of torrential rainstorms and accompanying flash floods that overwhelm drains and cause sewage outflows to back up in unseemly quantities where they are least expected or desired.
Finding creative ways to manage stream and river catchment areas may help address agricultural runoff as well as climate change. For example, using soils and vegetation as buffers can slow down rapid, pollutant-laden runoff during intense rainfall and help retain carbon. Also, designing catchments in preparation for drought and flash floods is an important adaptation technique, as both are likely consequences of climate change.
The key is to manage ecosystem services across the landscape so that the catchment acts as a unifying ecological whole. To achieve this, landowners and managers need to cooperate across natural drainage areas so that their activities are compatible with the functioning of water movement, soil stability, buffering vegetation, and reservoir location. By doing so, the catchment becomes a haven for new wetlands, which are flood soakaways for protecting property downstream. Soil conservation techniques, such as buffer zones along streams, reduce the flow of nutrients and toxic pesticides into surface water and groundwater resources. And the measures for retaining binding vegetative surfaces help keep rocks, trees, and sediment from clogging roads, drainage culverts, and the basements of commercial and residential property.
The environment is not the only beneficiary of such catchment care. Highway authorities gain by not having to invest in expensive road and culvert clearance programs; insurance companies can save on insurance claims; and water companies can reduce the expenditure on water treatment and the unpleasant clogging of sewage works.
Yet while coordination across property boundaries can benefit the greater public, such schemes pose a number of difficulties. Property rights become unclear, and because land management practices differ, the economic effects of meeting an ecosystem safeguard will vary greatly from one farm property to another. As a result, each will be affected differently by the expected land use prescription, and no clearly justified incentive structure will exist to encourage landowners to work together in this manner.
In addition, in the United States, Siikamaki notes that the biofuel market and strong crop prices already threaten land set aside under the U.S. Department of Agriculture's Conservation Reserve Program, because U.S. farmers can garner higher profits by planting on these environmentally sensitive areas-areas where soil can easily erode, such as along swales or stream banks-than by taking incentive cash from the government.
Another snag is the dearth of solid science behind the full benefit of a catchment's ecosystem services. Catchment care demands new institutional arrangements, which are being assessed by case study research. One method is to create excellent portraits of the ecosystems' functioning landscape by enhanced computer models. These will show how every field may have to be managed; it will also reveal the whole of the catchment benefit. Another possibility is to convene exchanges between beneficiary interests to encourage them to help finance the research. A third way is to demonstrate a good business case for creating soakaway wetlands. For example, water companies that invest in open areas near rivers benefit financially from an increase in recreational use as well as the reduction of sewage flooding.
Such schemes are in their infancy. The current interest in intensification of agriculture militates against these innovative ideas. But climate change is causing serious flooding and drought these days, which are proving very costly for business. Bringing the parties together for cooperative land use management is beginning to result in a whole new perspective. Sustainable catchment care is on the agenda, and long may it flourish.
Finding creative ways to manage stream and river catchment areas may help address agricultural runoff as well as climate change.
Copyright Heldref Publications Jul/Aug 2008
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