No. 118 irculation August 2013 Chilean hydrologyChilean hydrology CIRCULATION – THE NEWSLETTER OF THE BRITISH HYDROLOGICAL SOCIETY 1 Contents Chilean hydrology Chilean hydrology JAMES BATHURST (NEWCASTLE UNIVERSITY) The role of the hydrologist has been on sabbatical at the Universidad Austral de Chile at Valdivia during April-August 2013, as Environmental Clerk of researching the impact of forest plantation on Works soil erosion. Here he presents a personal view of Chilean hydrology and water resources. AGM Improbably thin, Chile stretches from within the tropics Peter Wolf Early Career to Cape Horn at a latitude equivalent to Edinburgh, Event providing just about every hydro-logical environment except tropical rain forest. North to south, it can be Urban aquatic ecosystems split into the Atacama desert (so dry that NASA uses it as a Mars analogue),a central region grading from EGU General Assembly Mediterranean climate (Santiago annual rainfall 360 mm) Impact of changes in the to temperate rain forest (Valdivia 2500 mm) and a cold and even more rainy southern region (over 3000 mm hydrological cycle in Patagonia). Water so defines the southern end of the Data-based mechanistic Central Valley that two of Chile’s administrative regions are named The Lakes and The Rivers. West-east there are methods for hydrological significant variations from the Coastal Cordillera, across modelling, forecasting and the Central Valley and into the Andes, where snowmelt emulation and glaciers form important water sources. Volcanoes and earthquakes add their own hydrological impacts. Knowledge for the future Hydrology at Lancaster Obit: Elizabeth M Shaw UK Hydrological Bulletin Letter to the Editor COVER PICTURE shows the outlet flume and gauging hut at the La Reina experimental catchment south of Valdivia. The catchment was set up in the mid 1990s in a DfID funded project involving Newcastle University and the then Volcán Osorno and the Petrohue Waterfalls. Institute of Hydrology (now the Centre for Ecology and Hydrology) in the transfer The climate is strongly affected by the El Niño of the SHETRAN modelling technology Southern Oscillation and is characterized by alternating to the Chilean Corporación Nacional sequences of wet and dry years. Since 2010 the country Forestal (CONAF). The Universidad has been enduring a severe drought, with the last decade Austral de Chile subsequently took over being the driest for 70 years. In May 2013, at the start of the operation of the station. The objects the austral winter, the nation’s reservoirs were on average on the roof are raingauges, not chimney in deficit by -71% relative to the normal May figure, with pots. The roof is the only open space many of the irrigation reservoirs at less than 5% capacity. available in an rather dense and rapidly It is predicted that four wet years are needed to recharge growing plantation forest. them fully. 2 CIRCULATION – THE NEWSLETTER OF THE BRITISH HYDROLOGICAL SOCIETY Agriculture is the main water user (63%), industry takes around 25% and domestic use is around 11%. Some double use of water occurs for hydropower. Most of Chile’s reservoirs are for hydropower and irrigation and most domestic water comes from river extraction or wells. Typically the hydropower reservoirs are built and owned by the generating companies while irrigation reservoirs involve much Ferry crossing the Río Baker in Patagonia. The Baker is one of greater state funding. The 1981 Water the two rivers that would be dammed in the proposed HidroAysén Code established a framework in HEP scheme. which free-market forces and water imports have driven up energy prices to the detriment markets were allowed to trade water of the country’s international competitiveness. The rights and enable the reallocation direct relationship between water and energy costs was of water to high-value uses, such as illustrated by a fascinating calculation in the leading daily fruit and wine. Known as the Chilean newspaper, El Mercurio, following the first heavy winter Model it had some success in its rains in May. The rainfall was translated into a runoff aims but did not take into account input to the reservoirs, which in turn was quantified as social considerations. In 2005 it a HEP resource of 180 MW, which in its turn allowed a was therefore reformed to address reduction in marginal energy costs (by replacing supply social equity and environmental from the hydrocarbon plants) from US$310 / MWh to protection concerns, so that for US$250 / MWh. example ecological water flows and A proposed hydroelectric scheme is also the cause sustainable aquifer management must of one of Chile’s biggest environmental disputes. The now be considered in the granting of HidroAysén scheme in Chilean Patagonia proposes new water rights. Too late, though, five dams on two rivers to generate 2750 MW at a for the northern rivers, where the construction cost (including the transmission line) of water rights were assigned before over US$10 billion. On the one hand the scheme would the environment was considered a generate much-needed and environmentally clean priority. In some cases the sum of the power and would provide job opportunities and support water rights exceeds the available development in a remote part of the country. On the water. other, it would devastate two of the world’s last few big Hydropower is at the centre of pristine rivers, would flood large areas (including part energy politics. Chile is long on renewable energy resources but short on conventional hydrocarbon resources and has to import, expensively, these latter fuels. A senior energy executive was recently quoted as saying that “Water is Chile’s oil” and indeed hydropower accounts for around 40% of Chile’s electricity generating capacity. Energy demand has greatly increased during Chile’s recent economic boom and its drive to become a fully developed nation by the end of the decade (it is the only South American nation in the OECD). However, the reduced HEP availability due Patagonia without dams! One of the protest posters against the to the drought and expensive fuel HidroAysén HEP scheme in Patagonia. CIRCULATION – THE NEWSLETTER OF THE BRITISH HYDROLOGICAL SOCIETY 3 of a national park) and, most controversially, would should be centralized to allow a more require a 2000-km transmission line driven through some integrated and efficient management. spectacular countryside to carry the electricity to the Increasing water demand has central and northern regions, presumably with significant generated a range of allocation losses along the way and open to disruption by a range of problems. The increasing amount geohazards. Critics also contend that Chile’s needs can be for irrigation is diverting water from met by a range of alternative renewable energy schemes, aquifer recharge, ecosystem services less environmentally disruptive and more broadly based and downstream wetlands. In the (implying a less vulnerable electricity supply). The desert north the demands of the mines scheme received government approval in 2011 but a (which account for over 40% of well-organized and somewhat unexpected opposition Chile’s export earnings) conflict with has delayed implementation. It is likely to feature in the domestic, agricultural, ecological campaigns for the November 2013 presidential election. and indigenous population needs. To Following a loss of momentum in recent decades, Chile avoid environmentalist censure, one once again has an active reservoir building programme. mining company has started to pump In March 2013 the government launched its National desalinated seawater from the coast Water Resources Strategy with the aim of ensuring that rather than deplete the local aquifer. water shortages should not be an obstacle to the country’s Pollution of rivers with mining development. Sixteen reservoirs have been proposed waste is also an issue and one large for construction by 2021, to increase the national water development has recently been storage by 30% and secure 170 000 ha of irrigation. As suspended until it builds satisfactory an indication of the growing demand for reliable water infrastructure for preventing such supply for agriculture, they include the first two irrigation pollution. In the south the realisation reservoirs in the southern rainy regions of The Lakes and that the extensive forest plantations The Rivers. The Strategy also includes the development can significantly affect runoff of new water sources such as aquifer recharge. Many quantity and quality is driving the of the aquifers are drying up through over exploitation development of Best Management and, apparently, reduced infiltration consequent upon soil Practice and environmental erosion (so more surface and less subsurface flow) and certification criteria for the forestry increasing urbanization (so more impermeable surface). companies. The conscious decision to concentrate on high value Detecting signs of climate change grapes (for wine) and other fruit for export, along with is hampered by the large interannual the drought and increasing energy and water costs, is fluctuations in conditions and also a driving changes in both the operation and management lack of hydrometeorological stations of irrigation. In particular, a reliable and efficient water in the Andes. The overall prediction, supply is needed if agriculture is to be internationally though, is for less rain and higher competitive. The older irrigation canals, built in the 19th temperatures and many of the and early 20th centuries as simple earth channels, lose Andean glaciers are indeed in retreat. 40–80% of their water into the ground and need to be Along with the glaciers, the winter lined. Furrow watering (which still accounts for 40% of snowpack is a crucial water resource. irrigation) needs to be replaced by the more efficient drip It enables water to be stored at the irrigation. The more advanced irrigation schemes are time of greatest precipitation (the also applying information technology and telemetry for winter) and released at the time of monitoring water availability and transfers (improving greatest irrigation need (the summer).