Quantifying the impacts of vegetation changes on catchment storage‐discharge dynamics using paired‐catchment data

Abstract

It is widely recognized that vegetation changes can significantly affect the local water availability. Methods have been developed to predict the effects of vegetation change on water yield or total streamflow. However, it is still a challenge to predict changes in base flow following vegetation change due to limited understanding of catchment storage‐discharge dynamics. In this study, the power law relationship for describing catchment storage‐discharge dynamics is reformulated to quantify the changes in storage‐discharge relationship resulting from vegetation changes using streamflow data from six paired‐catchment experiments, of which two are deforestation catchments and four are afforestation catchments. Streamflow observations from the paired‐catchment experiments clearly demonstrate that vegetation changes have led to significant changes in catchment storage‐discharge relationships, accounting for about 83–128% of the changes in groundwater discharge in the treated catchments. Deforestation has led to increases in groundwater discharge (or base flow) but afforestation has resulted in decreases in groundwater discharge. Further analysis shows that the contribution of changes in groundwater discharge to the total changes in streamflow varies greatly among experimental catchments ranging from 12% to 80% with a mean of 38 ± 22% (μ ± σ). This study proposed a new method to quantify the effects of vegetation changes on groundwater discharge from catchment storage and will improve our predictability about the impacts of vegetation changes on catchment water yields.

Evaluation of basin storage–discharge sensitivity in Taiwan using low‐flow recession analysis

“…As given in Table , a and b values ranged from 0.01 to 0.07 and from 0.64 to 1.67, respectively. Cheng et al () indicated that the functional relationship between water storage and discharge is derived from the slope of the recession curve generated by a logarithmic transformation between flow variation and flows. When other parameter values are fixed and the baseflow coefficient b is considered variable, the following three circumstances can be observed: (a) if b < 1, the slope value is small, indicating that the streamflow increases relatively slowly with increasing groundwater storages; (b) if b = 1, there is a linear relationship between groundwater storage and streamflow; and (c) if 1 < b < 2, the slope value is large, indicating that the streamflow increases relatively quickly with increasing groundwater storage.…”

“…Taking vegetation coverage as an example. Cheng et al () mentioned that the variation of recession curves changes with vegetation coverage. With decreasing vegetation coverage, the discharge of groundwater (baseflow) increases due to the decrease in groundwater evapotranspiration, thus reducing the baseflow recession rate.…”

Global Changes in Baseflow Under the Impacts of Changing Climate and Vegetation

“…From 27 studies on the effects of land use and land cover on groundwater recharge and surface runoff in semiarid tropical and subtropical regions, results also show that rehabilitation of bare land to cropland and forest results in a reduction of surface runoff and groundwater recharge, while the conversion of forest vegetation to bare land, rangeland, and cropland results in an increase in surface runoff (Owuor et al, 2016). Paired basin studies show a general consensus that vegetation greening (browning) leads to a decrease (increase) in mean streamflow due to increased (decreased) canopy interception and vegetation transpiration (Bosch & Hewlett, 1982; Brown et al, 2005; Cheng et al, 2017; Q. Li et al, 2018; Liu et al, 2015; Zhang et al, 2001). However, vegetation restoration can increase soil porosity and soil infiltration, thereby promoting groundwater recharge and possibly baseflow (Gu et al, 2018; Hansson et al, 2019; Liu et al, 2015).…”

Improving Representation of Deforestation Effects on Evapotranspiration in the E3SM Land Model

“…Deforestation is one of the most important forms of LULC change (Davin & de Noblet-Ducoudré, 2010;Lawrence & Vandecar, 2015;Lee et al, 2011;Li et al, 2016). The impacts of deforestation on hydrology are relatively well studied at paired catchments at small scale, with a general conclusion that deforestation decreases annual ET and increases land water yields (Brown et al, 2005;Cheng et al, 2017;Yurtseven et al, 2018;Zhang et al, 2001). At large scale, Earth system modeling is an important tool to study the climate effects of deforestation.…”