When every drop counts: addressing hydrologic connectivity as a climate change issue.

• Author: Lindsey, Max

1. INTRODUCTION

   Water is the resource that sustains populations and allows for the growth and expansion of society. Across the nation, from contaminated water sources (1) to depleted reservoirs, (2) conflicts over water supplies are becoming increasingly common. (3) One of the main drivers of these conflicts is the rapidly growing understanding of the effects of climate change on the water cycle. (4) The fact that climate change is affecting our world (5) and consequently our water system is an undeniable truth. (6) The disjointed, and often uncoordinated allocation of water rights across our country (7) is in drastic need of an overhaul in light of the evolving conditions of climate change. In order to fully appreciate all of the challenges and opportunities present in current water allocation regimes, each element of the water system needs to be independently analyzed and adapted to prepare for future changes. Some of the necessary changes and adaptations are easily recognized by the general public, (8) and therefore have seen a more rapid response from regulators aimed at tackling the issues before they cause greater problems for water use. (9) However, full understanding and adaptation to climate change requires an analysis of all elements of the water system and how they are affected by the impacts of climate change. (10)

   This note will focus on a relatively obscure and unrecognized aspect of the water system--hydrologic connectivity. (11) Due to the (until recently) largely unknown properties of groundwater flow and its connection to surface waters, hydrologic connectivity has been a historically underrepresented element of water law. (12) In order to effectively govern water rights allocations, the entire water system needs to be analyzed in the context of climate change to ensure the preservation of sufficient water for our whole country. There is not enough of this precious resource to let it fall through the gaps of our management systems. We need to adopt a holistic approach to accounting for climate change impacts on every element of the water system in an environment where every drop counts.

   This note will address the idea of hydrologic connectivity as a climate change issue through a multifaceted approach that looks at many impediments and advantages of adaptive management of hydrologic systems throughout the country. Part II touches on the current understanding of the impacts climate change has and will continue to have on water supplies and provides an overview of the current scope of adapting water rights to climate change. Part III provides an understanding of how hydrologic connectivity has developed as a water management device. Part IV identifies water regimes that have included hydrologic connectivity as a part of their management system and discusses whether these take into account the impacts of climate change. Part V addresses the specific implications of hydrologic connectivity and why this element is necessary to include in the adaptive management of water rights. Finally, Part VI identifies several challenges impeding the inclusion of hydrologic connectivity in adaptive water management systems and provides possible solutions to the problem of implementing such a comprehensive policy.

2. CLIMATE CHANGE IMPACTS ON THE WATER SYSTEM

   The scientific community has finally accepted the human contribution to climate change. (13) The impacts of climate change reach well beyond the common focus of increased temperatures on Earth, and these changes on Earth will impact nearly every aspect of human society over the next century. (14) Further, "[c]hanges in the global water cycle in response to the warming over the 21st century will not be uniform." (15) The changes to the water cycle will require an adaptive approach in order to evolve existing water institutions and policy to fit with climate change: "The likely hydrological effects of climate change will upset settled expectations and require water institutions to adapt." (16) While many impacts of climate change may seem like distant problems that only future generations will have to deal with, the impacts of climate change on precipitation patterns and water supplies are already very real elements of our society. (17) This reality has caused urgency for the adoption of more holistic and inclusive water management in face of its growing scarcity in some regions.

   "The legal system will struggle to reconcile 'secure' water rights and allocations ... with hydrological conditions, that will differ greatly from the assumptions on which those rights and allocations were granted." (18) Rather than looking to the past, water institutions of all scales and areas need to be forward-thinking in creating new and adaptive concepts for how to best manage water rights. (19) Given that there is now a lower extent of snow cover, uncertain changes to precipitation patterns, and an overall quicker rate of evaporation, the excess water that has traditionally recharged aquifers, rivers, and reservoirs may not exist to provide enough recharge in the near future. (20) As aquifers continue to be depleted and recharge rates are altered from the historical measurements, climate change continues to challenge water resources and existing approaches to groundwater allocations.

   The days of effectively allocating water rights based on historical data of hydrologic records are over. (21) Adaptive management is a way of addressing water institution regulation by looking forward to what is likely going to happen with regard to water supply, instead of looking back to mechanically rely on historical data of past experiences. (22) Recently, many scholars and resource managers have shifted to the thought that adaptive management is the preferred method of ecosystem and watershed management systems because of its ability to tailor management decisions to the changing elements being managed. (23) Despite this recognition by the intellectual community, there is still a large disconnect in the legal community and the process for allocating water rights. The fragmentation of water allocation systems between different governments, management systems, watershed basins, and other arbitrary (in terms of water flows) boundaries present difficulties in implementing adaptive management systems. (24)

   Most commentaries of adaptive watershed planning conclude that the best approach to water management is through an "integrated or holistic approach to the many aspects of watershed conditions and phenomena that affect water resources." (25) Still, many water allocation systems in the United States "give no real attention to the uncertainties in future conditions posed by climate change or the possible impacts of climate change on water resources and watershed sustainability." (26) Moreover, no water institution has yet analyzed how changing climate conditions are going to affect hydrologic connectivity. (27) If adaptive management is to be effectively implemented, then each aspect of the water system needs to be assessed in order to effectuate the most efficient use of water and allow for continued development without catastrophic depletion and overconsumption of our often-scarce resource. (28)

3. DEVELOPMENT AND UNDERSTANDING OF HYDROLOGIC CONNECTIVITY AS A WATER MANAGEMENT DEVICE

   "Modern Hydrological innovations have permitted more accurate tracing of groundwater movement. For this reason, we feel that traditional legal distinctions between surface and groundwater should not be rigidly maintained when the reason for the distinction no longer exists." (29)

   Several states govern groundwater and surface water through different regulatory schemes. (30) When groundwater and surface water are so interconnected, however, they must be analyzed as one common source for the proper allocation of water rights. (31) This hydrologic connection is being recognized throughout the United States in water rights disputes. (32) Still, the legal and scientific rationales supporting hydrogeology are not perfectly aligned, but they are moving to become more connected. As scientists and policymakers seek to maximize the water available to our expanding communities and water management becomes a more important process in light of the strained water supply in our nation, the "intertwined relationship between law and hydrogeology, which has had a long-established history, will become even more intimate in the future." (33)

   Typically, the legal system identifies "groundwater" as any water beneath the surface of the earth. (34) In contrast, hydrogeologists break this broad category into two distinct concepts: the zone of saturation and the zone of aeration. (35) The zone of aeration is the area underground that is not completely saturated with water, and the water in this zone is typically traveling downward with gravity toward the zone of saturation. (36) The zone of saturation, typically defined as an aquifer, is the area of groundwater in which all pores containing rock materials are saturated. (37) This is the area of the water table that allows water to be pumped out of the ground for human consumption. (38) The disconnect between law and science has joined all water under the earth into one broad regulatory scheme, making "every drop of the water beneath the surface ... potentially the subject matter of an administrative regulation or a lawsuit." (39) Groundwater is not a stagnant body sitting under the surface of the earth. It flows along a "hydraulic gradient," which pushes the water from areas where it is higher to where it is lower. (40) The typical residence time for water in a groundwater system averages a few hundred years, but "[t]he velocity with which groundwater moves in any given direction will be determined by permeability, hydraulic conductivity, porosity, and the hydraulic gradient." (41) Occasionally this movement causes a link between surface and groundwater, creating a hydrologic...