CNAS

Australia

Mac Kirby, CSIRO Land and Water

"Drought and climate change in the Murray-Darling Basin: A hydrological perspective."

In the Murray-Darling Basin, runoff and river flow are highly variable in both timing and magnitude. Drought is a common feature; the current drought is perhaps the most severe on record. The drought has greatly reduced water availability for irrigation, and for key environmental assets, particularly in the lower basin. With climate change, average water availability is likely to decline, and severe droughts are likely to be worse in the future. Over-allocation of water to irrigation is exacerbated by drought, and declining river health magnified. Drought and climate change increase the challenge of re-allocating water to the environment.

California

James Sickman, University of California Riverside, Department of Soil and Water Sciences

"Defining drought in California: Precipitation variability over annual to millennial time scales"

The dictionary defines drought as a long period of abnormally low rainfall, hence drought conditions are most commonly perceived as a function of supply rather than demand. In California, identifying drought is complicated by strong seasonality in precipitation and high interannual variability of annual rainfall amounts. This presentation will use snowpack and river flow data along with paleoclimatological records to examine precipitation variability in California and the western United States at annual to millennial time scales. Policy makers and society need to recognize that high variability is the normal condition for precipitation in California, and that drought conditions are driven as much by human demands for water as they are by precipitation patterns. 

Mexico

J. Joel Carrillo-Rivera, Institute of Geography, UNAM, México

"Where groundwater stands in drought conditions"

About 97% of the water present in the continents is groundwater. The rest includes surface-water, water in the atmosphere, and that in living organisms. These waters are constantly linked, so the understanding of their functioning is required for Mexico to cope with drought conditions and minimize environmental impacts due to actions related to water usage by humans. Groundwater moves in three dimensions from its recharge to its discharge zone in flow systems traveling through paths with different length and depth. An understanding of these systems is a base for Mexico to propose adequate policies for payment of hydrological environmental services. This chapter will discuss how changes in climatic conditions set an additional challenge to understanding how drought impact, using scientific knowledge and policy interventions, could be minimized to attain a sustainable management strategy. Interventions include control to applied subsidies for goundwater extraction and enhancement to forest protection.

South Africa

J. T. Vahrmeijera, and J. G. Annandale, University of Pretoria, Department of Plant Production and Soil Science, Pretoria, South Africa

"Drought: A catalyst for change – A case study of the Steenkoppies Dolomitic Aquifer under stress"

From the Steenkoppies Aquifer that covers an area of 213 km² with a catchment area of 311 km², water is abstracted for mainly vegetable and flower production. A perennial spring, Maloney’s Eye, serves as the only natural outlet for the groundwater stored in the aquifer. Hydrological drought enhanced by excessive abstraction provided the primary stimulus for change in the behavior and attitude of groundwater users, which resulted in processes being initiated to measure, monitor and manage water abstraction from the Steenkoppies Aquifer.

Spain

Joaquin Andreu et al., Instituto de Ingeniería del Agua y Medio Ambiente, Universidad Politécnica de Valencia

"Drought planning and management in the Júcar River Basin, Spain"

In the Jucar River Basin, water scarcity and hydrological variability produce frequent and long hydrological droughts. Preparation for droughts is achieved through a) integrated river basin planning, including proactive measures that minimize the risk of operative droughts (i.e., failure of the system to provide water services); b) special drought plans, including continuous monitoring in order to detect the risk in medium-short term management, and sets of measures for different scenarios; and c) participatory drought management by means of a special drought committee, to mitigate the impact of droughts and find compromise decisions to reach an equilibrium between economic sectors and environment . It will be illustrated how these three processes are applied in the recent 2004/2008 drought, and how they are very much enhanced and facilitated by the use of up to date integrative decision support systems.