Impact of climate and land use change on the hydrology of a large‐scale agricultural catchment

Abstract

[1] This paper presents a quantitative comparison of plausible climate and land use change impacts on the hydrology of a large-scale agricultural catchment. An integrated, distributed hydrological model was used to simulate changes in the groundwater system and its discharge to rivers and drains for two climate scenarios (2071-2100). Annual groundwater recharge increased significantly (especially the B2 scenario), giving higher groundwater heads and stream discharges and amplifying the seasonal dynamics significantly. Owing to drier summers, irrigation volumes increased by up to 90% compared to current values. Changing the land use from grass to forest had a minor effect on groundwater recharge, whereas CO 2 effects on transpiration resulted in a relatively large increase in recharge. This study has shown that climate change has the most substantial effect on the hydrology in this catchment, whereas other factors such as irrigation, CO 2 effects on transpiration, and land use changes affect the water balance to a lesser extent.

Linking Climate Change and Groundwater

“…The complexity of approaches for obtaining the climate data series appears to have increased in recent years, ranging from the use of global averages (Loaiciga et al 1996;Zektser and Loaiciga 1993) to the use of regional "bulk" projections (Allen et al 2004;Brouyere et al 2004;Vaccaro 1992;Yusoff et al 2002) to the direct application of downscaled climate data (Jyrkama and Sykes 2007;Scibek and Allen 2006b;Scibek et al 2007;Serrat-Capdevila et al 2007;Toews and Allen 2009) to the use of regional climate models (Rivard et al 2008;van Roosmalen et al 2007van Roosmalen et al , 2009). Some of the early efforts to assess potential hydrologic impacts were reviewed by Gleik (1986).…”

“…Tietjen et al (2009) made a case for at least two soil layers in a soil-vegetation model that simulated soil-water dynamics under different climatic conditions. Others have applied relatively complex, spatially distributed subsurface models and coupled surface-groundwater models (Goderniaux et al 2009;Hunt et al 2013;van Roosmalen et al 2007van Roosmalen et al , 2009). …”

Effect of Unsaturated Flow Model Conceptualization on the Dynamic Response of an Integrated Distributed Hydrological Model

“…The first one is a simple classification that was used in National Water Resources Model (Sakaguchi et al, 2005) and later by Van Roosmalen et al (2009). For the study area the soil was classified into two dominant soil types represented by fine and coarse sands respectively.…”

Sensitivity of groundwater recharge using climatic analogues and HYDRUS-1D

“…Three-meter deep soil profiles of Zcg (Belgian classification for sand, moderately drained, B horizon with obvious accumulation of organic matter and/or iron; FAO: Haplic Podzol, USDA: Aquic Haplorthod) and Zeg (sand, poorly drained, B horizon with obvious accumulation of organic matter and/or iron; FAO: Gleyic Podzol, USDA: Typic Haplaquod) soil series were used (Seuntjens et al, 2001). The most typical horizon sequence of these series and related texture and organic matter content properties were extracted from the Aardewerk soil information system (Van Orshoven et al, 1988). Grass rooting depth was arbitrarily set at 30 cm.…”

“…However, studies of the impact of climate change on groundwater recharge are usually restricted to time scales of several decades to hundreds of years (e.g. Goderniaux et al, 2009;van Roosmalen et al, 2009). This is because climate scenarios of such studies are often based on predictions of general climate models (GCMs) used in IPCC assessment reports (the latest of which is IPCC, 2007).…”