Hard and soft cap groundwater allocations: a comparison of groundwater pumping restrictions on hydrologic and economic outcomes

Young, Richael Kentlee

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https://hdl.handle.net/2142/99428 Copy

Description

Title

Hard and soft cap groundwater allocations: a comparison of groundwater pumping restrictions on hydrologic and economic outcomes

Author(s)

Young, Richael Kentlee

Issue Date

2017-12-14

Director of Research (if dissertation) or Advisor (if thesis)

Valocchi, Albert J.

Department of Study

Civil & Environmental Eng

Discipline

Environ Engr in Civil Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Groundwater
• Irrigation
• Agriculture
• Groundwater management
• Policy

Abstract

"While groundwater is an important primary and supplementary source of water in the western United States, its overuse can lead to negative consequences such as stream depletion, seawater intrusion, or land subsidence. An increasing number of groundwater management districts are restricting individual pumping in an effort to limit, or even reverse, such consequences. The nature of groundwater availability lends itself to more flexible allocation schemes, which I call ""hard caps"" and ""soft caps."" While a hard cap sets a groundwater user's maximum pumping in a single year, a soft cap allows a groundwater user to meet a multi-year average so that the user may pump more in some years and less in others. While there are many examples of hard and soft caps for groundwater in practice, no study to date has compared the resulting hydrologic and economic outcomes of each scheme. Using coupled agronomic, economic, and hydrologic models, I examine the performance of hard and soft caps for groundwater-fed irrigation. Irrigated agriculture uses the majority of groundwater in the United States and therefore the sector represents a significant stakeholder in the development of allocation schemes. I model the profit-maximizing decisions for an agricultural producer growing irrigated corn in western Nebraska. I illustrate the hydrologic and economic outcomes in the case of groundwater-induced stream depletion, which is a spatially and temporally heterogeneous consequence, or externality, of groundwater pumping. To do so, I combine datasets on regional climate, soils, economic parameters, and aquifer properties and use them as inputs to an instraseasonal crop-water model, an economic optimization, and a stream depletion model. I show that at moderate allocation levels, the soft cap results in higher expected profits and lower variance of profits. However, it can come at a cost: In exceptionally dry years, the soft cap can result in acute groundwater pumping, and therefore, stream depletion. The severity of this result depends on the hydrologic properties of the aquifer and well location. At non-binding or very binding allocation levels, the performances of the caps are similar. The implications for developing appropriately flexible allocations will depend on the combined needs for groundwater management and well-specific properties, meaning that a blended approach to caps in some instances may be desirable."

Graduation Semester

2017-12

Type of Resource

text

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http://hdl.handle.net/2142/99428

Copyright and License Information

Copyright 2017 Richael Kentlee Young

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