Progress on Nonpoint Pollution: Barriers & Opportunities

Book_Summer 2015_Shinner.qxd 6/17/2015 9:37 AM Page 35 Progress on Nonpoint Pollution: Barriers & Opportunities Adena R. Rissman & Stephen R. Carpenter Abstract: Nonpoint source pollution is the runoff of pollutants (including soil and nutrients) from agricultural, urban, and other lands (as opposed to point source pollution, which comes directly from one outlet). Many efforts have been made to combat both types of pollution, so why are we making so little progress in improving water quality by reducing runoff of soil and nutrients into lakes and rivers? This essay exam- ines the challenges inherent in: 1) producing science to predict and assess nonpoint management and policy effectiveness; and 2) using science for management and policy-making. Barriers to dem onstrating causality include few experimental designs, different spatial scales for behaviors and measured outcomes, and lags between when policies are enacted and when their effects are seen. Primary obstacles to using science as evidence in nonpoint policy include disagreements about values and preferences, disputes over validi- ty of assumptions, and institutional barriers to reconciling the supply and demand for science. We will illustrate some of these challenges and present possible solutions using examples from the Yahara Watershed in Wisconsin. Overcoming the barriers to nonpoint-pollution prevention may require policy-makers to gain a better understanding of existing scienti½c knowledge and act to protect public values in the face of remaining scienti½c uncertainty. Water is an important, dwindling resource. Water and aquatic ecosystems support industry, agricul- ture, outdoor recreation, aesthetic pleasure, aquatic food sources, and livelihoods. Massive, expensive ADENA R RISSMAN . is an Assis- efforts have been made to improve water quality tant Professor of the Human Di - and “repair what has been impaired.”1 These ef forts mensions of Ecosystem Manage- ment in the Department of Forest have led to some important gains, but water quality and Wildlife Ecology at the Uni- is still poor in many rivers, lakes, and coastal oceans. versity of Wisconsin–Madison. Runoff of soil, nutrients, and other chemicals from agricultural, urban, and other lands is called non- STEPHEN R. CARPENTER, a Fel- low of the American Academy since point source pollution. In contrast, point source 2006, is the Stephen Alfred Forbes pollution comes directly from a pipe, such as at an Professor of Zoology and the Di - industrial or municipal facility. Runoff of phospho- rector of the Center for Limnology rus–also called nonpoint phosphorus pollution– at the University of Wisconsin– is a major cause of toxic algae blooms, oxygen de - Madison. pletion, and ½sh kills in streams, lakes, and reser- (*See endnotes for complete contributor voirs.2 Why are we not making progress on nonpoint biographies.) source pollution in water quality? What are the chal - © 2015 by the American Academy of Arts & Sciences doi:10.1162/DAED_a_00340 35 Book_Summer 2015_Shinner.qxd 6/17/2015 9:37 AM Page 36 Progress on lenges of producing science to predict and tionists, farmers, ur ban homeowners, and Nonpoint assess nonpoint management and policy lake managers. We will illustrate how sci- Pollution: Barriers & effectiveness, and of using this science in enti½c information has been created and Opportu - management and political decisions? used to improve water quality in Wiscon- nities Finally, what changes are needed to im - sin’s Yahara Watershed, fo cusing on wa - prove water quality? tershed nonpoint-pollution reduction and A major scienti½c enterprise is devoted in-lake biomanip ulation. to producing scienti½c knowledge to in - Water pollution is typically viewed as form nonpoint policy and management an externality that does not directly sub- through long-term monitoring, statistical tract from the productivity of those re - analysis, and modeling. But is scienti½c sponsible for the pollution, except indi- knowledge actually reducing uncertainty rectly or through social limits. This means about the causes of water-quality impair- that producers of pollution are not inher- ment and the effectiveness of control mea - ently incentivized to remedy it; the issue sures? Researchers are increasingly vocal of assigning responsibility becomes even about the challenges facing nonpoint- more dif½cult with the diffuse nature of pollution science on sediment, phospho- nonpoint source pollution. The dif½cult is - rus, nitrogen, and other pollutants.3 For sue of nonpoint source pollution has led instance, it is well-established that end- to a proliferation of blended regulatory, of-pipe mitigation of phosphorus im proves in centive, and collaborative efforts to en - water quality, but proving the ef fectiveness gage homeowners, municipal stormwater of actions to control nonpoint-source systems, and farmers in reducing nu tri - phosphorus is challenging. It is ex tremely ent and sediment runoff.7 dif½cult to demonstrate causality when Building scienti½c evidence for nonpoint con necting water-quality conditions to pol - pollution is long, slow, and scale-depend- icies and the behaviors of agricultural and ent. Given the rapid changes taking place urban residents. An increase in knowledge in ecological and social systems, is the base - and data has therefore not always trans- line moving faster than we can learn? We lated to more effective policy. suggest that, in addition to science, po liti - Once scienti½c knowledge is produced, cal will and public val ue should play a great - why is it so dif½cult to use it as evidence in er role in decision- making to improve en - nonpoint pollution–related policy-mak- vironmental outcomes. ing and management? Science does not de termine public interests and values, but There are a number of dif½culties in her - it can serve important purposes in policy- ent in producing knowledge about non- making and resource management.4 It can point- pollution control. First, a growing identify problems, prioritize the location number of studies from around the world or type of interventions, identify the likely show that it is extremely dif½cult to de - effects of actions before they are taken (in - ter mine the ef½cacy of interventions aim - cluding anticipating unintended ef fects), ing to reduce nutrient runoff from wa ter - and evaluate the effects of actions after sheds. In many cases, freshwater qual ity they are taken.5 Science and society affect has not been found to have recovered even each other deep ly.6It is important to un der - after decades of nutrient management,8 stand how sci enti½c evidence, models, un - and the divergent explanations for lack of certainty, and risk enter into the decisions suc cess reflect the complexity of water- of actors such as the Environmental Pro- sheds as social-ecological systems.9 De - tection Agency (epa), county conserva- spite the urgent need for management in - 36 Dædalus, the Journal ofthe American Academy of Arts & Sciences Book_Summer 2015_Shinner.qxd 6/17/2015 9:37 AM Page 37 terventions to protect freshwaters, there is ment.11 Time lags ranging from one to Adena R. a high level of uncertainty about the ef½ - more than ½fty years have been measured Rissman & Stephen R. cacy of methods; indeed, there may be between the initiation of a management Carpenter fun da men tal limits to our knowledge of intervention and the observation of an this subject. It is not clear whether water- environmental response.12 Projections es - shed man agement is making progress on timate that interventions to cut off phos- un cer tain ty; for now, the success or fail- phorus fertilization of soil will take two ure of policies may be a matter of luck rath - hundred and ½fty years to produce a new, er than knowledge. For this reason, it is low-phosphorus equilibrium in the agricul - im por tant to consider the barriers to the tural lands of a Wisconsin watershed.13 production of knowledge about nu tri ent In a diverse set of watersheds, re sponse pol icy and man agement and the op por tu- times for nutrient interventions ranged nities to im prove scienti½c under stand ing from less than one year to more than one in this area. We will explore the reasons for thousand.14 Such long time lags pose ser - the dif½cul ty of demonstrating causal ef - ious dif½culties for scienti½c in ference and fects of nu trient-management pol icies in for sustaining the engagement of the pub - large water sheds, including: long time lags lic and policy-makers. between intervention and response, spa- Furthermore, many factors that affect tial hetero geneity (that is, a solution that water quality change simultaneously. For works in one site may not work in an - example, precipitation, land use, agricul- other), simultaneous changes in multiple tural management practices, and ecologi- pollution driv ers, and lack of monitoring. cal characteristics of lakes and streams are Nonpoint pollution–management pro- always changing.15 Effects of management grams involve large areas with multiple interventions to improve water quality nutrient sources; many individual land must be discerned against this background managers; spatially heterogeneous topog - of multiple changing drivers, each of raphy, soils, and ecosystems; and diverse which affects water quality. The lengthy streams and lakes. Speci½c practices for response time of the environment com- ameliorating pollution–such as buffer pounds this dif½culty. Ecosystem scientists strips, cover crops, tillage practices, and generally employ an array of ap proaches, wetland restoration–are usually tested on including observing paired reference eco - relatively homogenous sites at scales of a systems, to distinguish between the effect few hectares for a few years. While these of the intervention and that of other methods are effective in short-term, small- changing drivers.16 However, these tools scale ½eld trials, little is known about how of inference are rarely applied to non point they scale up to whole watersheds.10 At pollution–management programs.

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