David B. Willis

Ecosystem services provided by playas in the High Plains: potential influences of USDA conservation programs

Playas are shallow depressional wetlands and the dominant wetland type in the non-glaciated High Plains of the United States. This region is one of the most intensively cultivated regions in the Western Hemisphere, and playas are profoundly impacted by a variety of agricultural activities. Conservation practices promoted through Farm Bills by the U.S. Department of Agriculture (USDA) that influence playas and surrounding catchments impact ecosystem functions and related services provided by wetlands in this region. As part of a national assessment, we review effects of agricultural cultivation and effectiveness of USDA conservation programs and practices on ecosystem functions and associated services of playas. Services provided by playas are influenced by hydrological function, and unlike other wetland types in the United States, hydrological function of playas is impacted more by accumulated sediments than drainage. Most playas with cultivated catchments have lost greater than 100% of their volume from sedimentation causing reduced hydroperiods. The Conservation Reserve Program (CRP) has the largest influence on playa catchments (the High Plains has >2.8 million ha), and associated sedimentation, of any USDA program. Unfortunately, most practices applied under CRP did not consider restoration of playa ecosystem function as a primary benefit, but rather established dense exotic grass in the watersheds to reduce soil erosion. Although this has reduced soil erosion, few studies have investigated its effects on playa hydrological function and services. Our review demonstrates that the Wetlands Reserve Program (WRP) has seldom been applied in the High Plains outside of south-central Nebraska. However, this is the primary program that exists within the USDA allowing conservation practices that restore wetland hydrology such as sediment removal. In addition to sediment removal, this practice has the greatest potential effect on improving hydrologic function by reducing sedimentation in vegetative buffer strips. We estimate that a 50-m native-grass buffer strip could improve individual playa hydroperiods by up to 90 days annually, enhancing delivery of most natural playa services. The potential for restoration of playa services using USDA programs is extensive, but only if WRP and associated practices are promoted and playas are considered an integral part of CRP contracts.

Effectiveness of Two Water Conservation Policies: An Integrated Modeling Approach

Agriculture in the Texas High Plains depends entirely on the Ogallala Aquifer. Texas enacted water conservation legislation to address declining reserves in the aquifer. We developed an integrated regional water policy model that links a hydrology model with an economic optimization model to estimate policy impacts with respect to economic cost and water conservation. Testing the effectiveness of two policies, a groundwater extraction tax and extraction quotas, we observe that neither significantly inhibits groundwater use. Although both policies conserve similar amounts of groundwater, the regional cost of the tax policy to agriculture is more than the quota policy.

Economic Value of Angling at a Reservoir with Low Visitation

Abstract A travel cost model was used to estimate the per-day consumer surplus for anglers at a reservoir (Lake Kemp, Texas) with low visitation. The average per-day consumer surplus for anglers was

Discussion: Water Scarcity–Future Uses and Implications for Policy

61–122, depending on the wage rate fraction assigned to the opportunity cost of time. Although this consumer surplus value is small, anglers on the numerous smaller public and private water bodies may, in aggregate, generate a majority of the economic value for freshwater angling. Further, the marginal value per dollar spent managing small water bodies is probably large. Arguably, greater attention should be directed toward managing our nations numerous smaller water bodies.

A Coasian Approach to Efficient Water Allocation of a Transboundary River

The three articles presented at this invited session examine the evolution of water policy planning and the implementation of regulatory tools to achieve water conservation objectives. Two articles focus on Texas water issues and the third focuses on the Georgia planning experience. Each article clearly illustrates the value of sharing advances in hydrologic and economic modeling with local community stakeholder groups to facilitate the credible development of regional water management plans. Moreover, each article hints that stronger regulatory tools may be needed to achieve long-run policy objectives.

Low Impact Development Decision-Making to Evaluate Impacts of BMP Selection

The United States and Mexico recently resolved a decade-old water dispute that required Mexico to repay the accumulated water debt within one year. A Coasian analysis estimates the social welfare gains attainable to each country under an alternative debt repayment scheme that allows repayment over a longer time horizon and in a combination of dollars and water, instead of solely in water. Assuming average water supply conditions, under the agreed 1-year repayment contract, U.S. compensation value is 534% greater and Mexico’s compensation cost is 60% less relative to when compensation is paid exclusively in water.

Towards A Comprehensive Regional Water Policy Model For The Texas High Plains

As upstate South Carolina continues to develop, stormwater runoff must be managed for its quantity and quality. Therefore, an incentive-based program to encourage developers to use low impact development (LID) designs is being developed for Greenville County. To achieve this goal, various best management practices (BMPs) were researched for their effectiveness and feasibility, and a post construction index (PCI) was developed to rate development. The PCI helps address questions about the benefit of small structures scattered around a development as compared to larger structures located near the outlet point and also considers economics of BMPs. The PCI is related to available parameters to scientifically anchor the PCI and make it directly related to stormwater runoff and water quality characteristics that reflect benefits of structural, non-structural, management and maintenance practices. The PCI is a function of nine (9) defined sub-factors with each having a range from zero to a maximum score of 5, 10, 15 or 20. Total scores for all sub-factors are used to differentiate between the water quality impacts of legacy, conventional, and innovative housing developments/LID designs.