367soil erosion are the prevailing land degradation issues in Pakistan (Sharda 2011 ).
Irrigation systems in Pakistan are now underperforming, and groundwater use is
increasing, leading to soil salinity. The major challenge is to improve productivity
levels by managing water resources in an integrated way to benefit the people and
the environment (IWMI 2015 ).
Sri Lanka has per capita water resources availability of 2400 m^3 with an average
annual rainfall of 1712 mm (Ariyabandu 2008 ). Rainfall ranges from less than
1250 mm in the northwest and southeast to more than 5080 mm in the southwest.
There are two rainfall zones in Sri Lanka namely, dry zone and wet zone (Kumar
2011 ); some districts of Sri Lanka experience prolonged dry periods due to the high
temporal and spatial variability of rainfall. Sri Lanka has the second highest annual
variability of rainfall of 22 Asian and Pacific countries. Even though the per capita
availability of water is higher than many other countries, the scarcity of water is
starting to threaten Sri Lanka's development (Ariyabandu 2008 ). Demand for water
has increased and, at the same time, its availability has been affected by prolonged
dry spells and droughts, and the pollution of sources. The Ministry of Environment
and Natural Resources ( 2002 ) in Sri Lanka states that 85 % of developed water is
used for irrigation, 6 % is for domestic use and 5 % is for industry. The number of
wells and irrigation pumps has increased resulting in the indiscriminate withdrawal
of groundwater from aquifers, which seriously threatens the sustainability of
groundwater. Nearly 30 % of the population lives in coastal areas and depends on
the shallow lens of freshwater saddled on saline waters for their livelihood, and the
precious and limited water resources are threatened by over extraction, pollution,
saltwater intrusion and rising sea levels due to climate change. A systematic research
program is urgently needed to guide the policy, legislation and institutions that
include adaptation to climate change (IWMI 2010 ).
Rainfall in Nepal varies spatially from more than 1300 mm in Kathmandu to
more than 6000 mm along the southern slopes of the Annapurna Range in central
Nepal to less than the 250 mm in the north central part near the Tibetan plateau.
Rainfall amounts ranging from 1500 mm to 2500 mm are predominant over most
parts of the country. High mountains cover nearly 35 % of the geographical area,
middle mountains cover nearly 42 %, and the Tarai region covers nearly 23 %
(Kumar 2011 ). Major problems include soil erosion, deterioration of soil quality,
waterlogging along canal systems, quarrying which denudes hill slopes, excessive
erosion, and the accumulation of debris in rivers (Sharda 2011 ). The government
has adopted the principles of Integrated Water Resources Management (IWRM)
and River Basin Management for planning and managing water resources (IWMI
2015 ). Global warming is expected to cause changes in the timing of monsoonal
rains and the release of snow and glacier melt. In Nepal, nearly 30 million people
are vulnerable to recurrent floods, landslides and droughts, and more than 80 % of
the population depends on agriculture, which consumes 99 % of water withdrawn,
but only 24 % of arable land is irrigated. The poorly-managed watersheds increase
the stress and decrease the sustainability of water resources. The drying up of water
sources, reduced surface and groundwater flows, and pollution are adversely affect-
ing the domestic water supply demands for the increasing population.
Dryland Agriculture in South Asia: Experiences, Challenges and Opportunities