to devastating floods and mudslides, mainly due to heavy precipitation on degraded upper basins, whereas the southern part of the country is particularly prone to droughts. aside from natural causes, such as el niño southern oscillation, the effects of droughts and floods have been exacerbated by manmade interventions including soil erosion stemming from poor cropping and grazing practices, deforestation, and poor land use-practices. el niño hits peru approximately once every seven years and consists of heavy winds and rainfall associated with devastating floods and landslides. in 1997–1998 the costs of damages reached us$2 billion. droughts severely affect the southern coast, producing agricultural losses as well as limitations on human water consumption. preventive laws and measures (related to zoning, deforestation, and so forth) are not enforced and there is no reliable early warning system. the consequence is increasing negative impacts from droughts and floods on the different regions, with an increasing impact on peru's economy. potential climate change effects yerupaja although a thorough assessment of the net impacts on peru's water resources is still lacking, some trends are discernible. the effects of climate change in peru include more extreme weather conditions such as droughts and floods, el niño southern oscillation, increased likelihood of flash fires, changes in the ability of ecosystems to store water, and the retreat of andean glaciers. the effects of glacier retreat are different at the initial and final stages of glacier retreat—initially more water is available during the dry season, while flow declines below the initial level once the glacier has melted. (see impacts of glacier retreat in the andes:documentary). high mountain ecosystems, including páramos (unique wetlands of the northern andes) and snowcapped terrains are among the environments most sensitive to climate change. these ecosystems have unique endemic flora and provide numerous valuable environmental goods and services. data recently made available suggest that climate impacts have already altered the circulation patterns responsible for producing and moving water vapor to the region. these changes have likely contributed to the disappearance of high-altitude water bodies, as well as to the increased occurrence of natural and human-induced mountain fires. the program for strengthening of national capacities to manage the impact of climate change and air pollution (proclim) together with the ministry of environment and the netherlands cooperation agency published a model for adaptation that estimated the impacts of climate change climate for several river basins. for instance, in the mantaro river basin one scenario presents a possible increase (greater than 50%) in precipitation along the entire basin, particularly over the west central mountain range and the chinchaycocha plateau. according to a second scenario, precipitations in the west central range could increase in more than 100% while in the eastern region they could be reduced by 20%. in the piura river basin there is a (i) tendency towards increase of the minimum temperature peaks and the average sea level; (ii) greater probability that the intensity of future el nino events will increase; (iii) there will be an occurrence of an el nino phenomena during the 2009–2015 period similar to the one of 1982–1983; (iv) a deficit in the balance of water is foreseen during the period 2005–2035; and (v) tendency towards lengthier and more frequent drought periods is noticeable. in the cordillera blanca, santa river basin precipitations will become the main water resource in view of the severe retreat of the area's tropical glaciers. because of the tendencies towards temperature increase, it is expected that the runoff levels will increase until they reach a peak in the first half of the century, to then exhibit a sustained decline in water resources. public perceptions related to water and climate change according to a 2008 survey of radio rpp, only 37% of respondents think that water is scarce in peru. only 27% of respondents living in lima—a city in the middle of a desert—believe water to be scarce in lima. 72% of respondents throughout the country believe that peru is affected by climate change. however, only 8% of respondents think that water scarcity is a consequence of climate change. ongoing programs and initiatives the government is currently looking into seawater desalination as a national priority to adapting to decreasing water availability. peru's government in planning a us$1.5 billion investment to build two desalination plants on lima's coast to supply water to 1.5 million people. the world bank is collaborating with the government of peru through the national water resources management modernization project (us$10 million). this project aims at strengthening the institutional capacity for integrated water resources management at the national level and in three river basins namely, chancay-lambayeque, ica-alto pampas and chili. the world bank is also contributing us$85 million, out of a total of us$172.4 million, to a subsectoral irrigation project (programa subsectorial de irrigacion). also, the agricultural research and extension adaptable program loan phase 2 (us$69 million) aims to promote the adoption of sustainable agricultural practices in glacier-dependent watersheds. in june 2007, the global environmental facility approved the regional adaptation to the impacts of rapid glacier retreat in the tropical andes (bolivia, ecuador and peru) project. this project aims at implementing adaptation measures to meet the anticipated consequences of glacier retreat induced by climate change. the inter-american development bank (idb) contributes us$10 million to a water resources management modernization project focused on three pilot river basins namely, santa, chira-piura and tacna. this project does not include any intervention at the national level. in june 2007, the idb approved us$200 million for a water resources reform program (wrrp) that would include hydraulic structures, and institutional and legal reforms. in august 2007, the idb approved an additional us$5 million to support capacity building efforts contained in the wrrp. the idb is also implementing a water resources management plan for peru's maschón and chonta watersheds. the objective of this us$1.2 million grant is to define the appropriate measures for improving integrated water resources management.