Analyzing the Effects of Land Cover Change on the Water Balance for Case Study Watersheds in Different Forested Ecosystems in the USA

Nathan C Healey,Jennifer A Rover

doi:10.3390/land11020316

Abstract

We analyzed impacts of interannual disturbance on the water balance of watersheds in different forested ecosystem case studies across the United States from 1985 to 2016 using a remotely sensed long-term land cover monitoring record (U.S. Geological Survey Land Change Monitoring, Assessment, and Projection (LCMAP) Collection 1.0 Science products), gridded precipitation and evaporation data, and streamgaging data using paired watersheds (high and low disturbance). LCMAP products were used to quantify the timing and degree of interannual disturbance and to gain a better understanding of how land cover change affects the water balance of disturbed watersheds. In this paper, we present how LCMAP science products can be used to improve knowledge for hydrologic modeling, climate research, and forest management. Anthropogenic influences (e.g., dams and irrigation diversions) often minimize the impacts of land cover change on water balance dynamics when compared to interannual fluctuations of hydroclimatic events (e.g., drought and flooding). Our findings show that each watershed exhibits a complex suite of influences involving climate variables and other factors that affect each of their water balances differently when land cover change occurs. In this study, forests within arid to semi-arid climates experience greater water balance effects from land cover change than watersheds where water is less limited.

Highlights

We aim to address the questions: (1) Does land cover change in forested ecosystems with different disturbance regimes play a leading role in changes to the water balance in the United States? and (2) What relative roles do land cover change and precipitation play in changing the water balance in forested ecosystems with different disturbance regimes?
To investigate how land cover data with annual temporal frequency could inform a variety of hydrologic studies, we examined annual land cover change along with precipitation, streamflow, and evaporation patterns to elucidate how land change affects the water balance in watersheds with both relatively stable or changing
We found that land cover change can have a large impact on evaporation, streamflow, and resulting water storage

Summary

Introduction

Connections between land cover change and watershed hydrology have been examined at a variety of spatial and temporal scales [1,2,3]. The roles of climate and land use changes vary from watershed to watershed because when, where, and how processes occur all have different impacts on hydrology and are dependent on landscape position and timing of events such as precipitation and drought [1,4]. Previous studies have investigated the relative importance of how precipitation and land use/land cover changes affect streamflow and found that both factors affect hydrology [8]. Generalization of various land cover and climate controls on watershed hydrology in different environments is attainable but requires sufficient data and knowledge of site-specific land cover change, precipitation patterns, geomorphology, and human activities. Positive and negative feedbacks vary with time, producing short-term responses potentially differing from long-term responses

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