Amicus Brief on Ecosystem Services in the ACF Equitable Apportionment Proceeding

30 Pages Posted: 22 Feb 2017  

J. B. Ruhl

Vanderbilt University - Law School

Date Written: February 20, 2017


A river is more than water flowing downhill. It follows that equitable apportionment doctrine is about more than just how much water must flow downhill across a state line. While that quantum is often the end product of an interstate river equitable apportionment decree, the underlying question the doctrine must answer to designate such a quantum is, “What is being allocated, and on what basis?”

The purpose of this amicus brief is to present the case for using principles from the scientific discipline of “ecosystem services” to help answer that question, specifically in this proceeding but also more generally for the doctrine. Ecosystem services are the benefits humans receive from natural resources in the form of goods, such as water, fish, and timber, and of services, such as groundwater recharge, flood mitigation, and salinity regulation, many of which are public or quasi-public goods and thus not easily accounted for in markets.

It should come as no surprise that there are ecosystem services — that natural resources like rivers are not only ecologically important but also economically valuable to human communities. Nevertheless, a discipline centered on the study of ecosystem services did not emerge robustly until the mid-1990s, when ecologists, economists, geographers, and researchers from other traditionally siloed fields began coming together to focus on the identification and quantification of ecosystem services.

The composition, distribution, and human consumption of ecosystem services are among the attributes that make a river more than water flowing downhill. Water extracted from a river in its physical form is not the only ecosystem service humans consume from a river. They also consume flood mitigation services, estuarine salinity regulation services, habitat maintenance services for commercial fisheries, and a suite of other economically valuable benefits made possible in large part by the water flowing in its physical form down the river. The fact that some of these services seem “ecological” and are not easily monetized in commercial markets does not make them any less economically valuable when humans consume them. It follows that equitable apportionment doctrine ought to take into account all of the ecosystem services humans consume from a river and allocate the water flowing downhill so as to provide an equitable division of those services between the states.

Indeed, I argue in this brief that the Court’s equitable apportionment doctrine already incorporates all of the key principles behind the concept of ecosystem services, though not in the language and metrics used in ecosystem services science. The language of equitable apportionment doctrine has lagged behind the science of ecosystem services for the simple reason that the Court has not had a proceeding like this one since the ecosystem services discipline emerged to synthesize and galvanize scientific research. But the spirit of the ecosystem services concept has been embedded in equitable apportionment doctrine for decades. Its spirit has taken material form in other legal domains from federal and state statutes to agency regulations and policies to judicial common law decisions. This original jurisdiction proceeding presents the opportunity for the ecosystem services concept to become explicit and inform decisions in yet another legal domain — the Court’s doctrine of equitable apportionment.

Part I of this brief provides the Court background on the discipline of ecosystem services. Part II traces developments in law and policy integrating ecosystem services principles, including a recent White House directive to federal agencies, to demonstrate that it has gained traction in legal domains related to equitable apportionment. Part III argues that it is fully consistent with the Court’s equitable apportionment doctrine to incorporate ecosystem services principles to help resolve the apportionment decision. Finally, Part IV suggests ways in which doing so will help clarify resolution of the equitable apportionment issues presented in this proceeding regarding the Apalachicola-Chattahoochee-Flint River Basin (“ACF”). Indeed, there has perhaps been no equitable apportionment case in the Court’s history that more starkly and imperatively makes the case for using principles of ecosystem services to guide the apportionment decision.

Keywords: Ecosystem Services; ACF; Equitable Apportionment

Suggested Citation

Ruhl, J. B., Amicus Brief on Ecosystem Services in the ACF Equitable Apportionment Proceeding (February 20, 2017). Vanderbilt Law Research Paper. Available at SSRN: or

J. B. Ruhl (Contact Author)

Vanderbilt University - Law School ( email )

131 21st Avenue South
Nashville, TN 37203-1181
United States

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