EVALUATION OF IMPACT OF LAND USE CHANGE AND CLIMATE CHANGE ON DISTRIBUTION OF WATER RESOURCES IN TOYAMA BASIN BY USING DISTRIBUTED WATER BALANCE MODEL

Author(s):  
Takuya MATSUURA ◽  
Taichi TEBAKARI ◽  
Akira TOMIGASHI ◽  
Riku OGATA
2007 ◽  
Vol 4 (6) ◽  
pp. 4265-4295 ◽  
Author(s):  
J. Dams ◽  
S. T. Woldeamlak ◽  
O. Batelaan

Abstract. Land-use change and climate change, along with groundwater pumping are frequently indicated to be the main human-induced factors influencing the groundwater system. Up till now, research has mainly been focusing on the effect of the water quality of these human-induced changes on the groundwater system, often neglecting changes in quantity. The focus in this study is on the impact of land-use changes in the near future, from 2000 until 2020, on the groundwater quantity and the general hydrologic balance of a sub-catchment of the Kleine Nete, Belgium. This study tests a new methodology which involves coupling a land-use change model with a water balance model and a groundwater model. The future land-use is modelled with the CLUE-S model. Four scenarios (A1, A2, B1 and B2) based on the Special Report on Emission Scenarios (SRES) are used for the land-use modelling. Water balance components, groundwater level and baseflow are simulated using the WetSpass model in conjunction with a MODFLOW groundwater model. Results show that the average recharge slowly decreases for all scenarios, the decreases are 2.9, 1.6, 1.8 and 0.8% for respectively scenario A1, A2, B1 and B2. The predicted reduction in recharge results in a small decrease of the average groundwater level, ranging from 2.5 cm for scenario A1 to 0.9 cm for scenario B2, and a reduction of the total baseflow with maximum 2.3% and minimum 0.7% respectively for scenario A1 and B2. Although these average values do not indicate significant changes for the groundwater system, spatial analysis of the changes shows the changes are concentrated in the neighbourhood of the major cities in the study areas. It is therefore important for spatial managers to take the groundwater system into account for reducing the negative impacts of land-use and climate change as much as possible.


2005 ◽  
Vol 2 (3) ◽  
pp. 821-861
Author(s):  
M. A. Bari ◽  
K. R. J. Smettem

Abstract. A simple conceptual water balance model representing the streamflow generation processes on a daily time step following land use change is presented. The model consists of five stores: (i) Dry, Wet and Subsurface Stores for vertical and lateral water flow, (ii) a transient Stream zone Store (iii) a saturated Goundwater Store. The soil moisture balance in the top soil Dry and Wet Stores are the most important component of the model and characterize the dynamically varying saturated areas responsible for surface runoff, interflow and deep percolation. The Subsurface Store describes the unsaturated soil moisture balance, extraction of percolated water by vegetation and groundwater recharge. The Groundwater Store controls the baseflow to stream (if any) and the groundwater contribution to the stream zone saturated areas. The daily model was developed following a "downward approach" from an earlier monthly model and performed very well in simulating daily flow generation processes observed at Ernies (control) and Lemon (53% cleared) catchments in Western Australia. Most of the model parameters were incorporated a priori from catchment attributes such as surface slope, soil depth, porosity, stream length and initial groundwater depth, and some were calibrated by matching the observed and predicted hydrographs. The predicted groundwater depth, and streamflow volumes across all time steps from daily to monthly to annual were in close agreement with observations for both catchments.


Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 40
Author(s):  
Nick Martin

A framework for the assessment of relative risk to watershed-scale water resources from systemic changes is presented. It is composed of two experiments, or pathways, within a Monte Carlo structure and provides quantification of prediction uncertainty. One simulation pathway is the no change, or null hypothesis, experiment, and the other provides simulation of the hypothesized system change. Each pathway uses a stochastic weather generator and a deterministic water balance model. For climate change impact analysis, the framework is calibrated so that the differences between thirty-year average precipitation and temperature pathway values reproduce climate trends. Simulated weather provides forcing for identical water balance models. Probabilistic time histories of differences in actual evapotranspiration, runoff, and recharge provide likelihood per magnitude change to water resources availability. The framework is applied to a semi-arid watershed in Texas. Projected climate trends for the site are a 3 °C increase in average temperature and corresponding increase in potential evapotranspiration, no significant change in average annual precipitation, and a semi-arid classification from 2011–2100. Two types of water balance model are used in separate applications: (1) monthly water balance and (2) daily distributed parameter. Both implementations predict no significant change, on average, to actual evapotranspiration, runoff, or recharge from 2011–2100 because precipitation is unchanged on average. Increases in extreme event intensity are represented for future conditions producing increased water availability during infrequent events.


1997 ◽  
Vol 28 (4-5) ◽  
pp. 273-282 ◽  
Author(s):  
C-Y Xu ◽  
Sven Halldin

Within the next few decades, changes in global temperature and precipitation patterns may appear, especially at high latitudes. A simple monthly water-balance model of the NOPEX basins was developed and used for the purposes of investigating the effects on water availability of changes in climate. Eleven case study catchments were used together with a number of climate change scenarios. The effects of climate change on average annual runoff depended on the ratio of average annual runoff to average annual precipitation, with the greatest sensitivity in the catchments with lowest runoff coefficients. A 20% increase in annual precipitation resulted in an increase in annual runoff ranging from 31% to 51%. The greatest changes in monthly runoff were in winter (from December to March) whereas the smallest changes were found in summer. The time of the highest spring flow changed from April to March. An increase in temperature by 4°C greatly shortened the time of snow cover and the snow accumulation period. The maximum amount of snow during these short winters diminished by 50% for the NOPEX area even with an assumed increase of total precipitation by 20%.


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