Effects of irrigation system
management turnover on
water table depth and salinity of groundwater
Kemal Sulhi Gundogdu*
and S. Tulin Akkay Aslan
1Agricultural Structures and Irrigation Department, Agricultural
Faculty, Uludag
University, Bursa-16059, Turkey
(Received:
January 1, 2006 ; Revised received: July 4, 2006 ;
Accepted: October 8, 2006)
Abstract: In recent years, management of large,
state owned irrigation projects in Turkey have been transferred to
water users such as farmers cooperatives or
associations in order to reduce the financial burden on the government and to
increase irrigation efficiency and farmer participation. Water table depth and
groundwater salinity are important factors in irrigation systems, not only for
plant growth but for human health as well. The objective of this study was to
determine the impact on water table depth and groundwater salinity for
transferring management of the Mustafakemalpasa
irrigation project (19,370 ha) in north-western Turkey to local, farmer controlled
irrigation districts. Maps of water table depth and groundwater salinity were
created for the month of July (averaged over several years), the month with the
highest amount of applied irrigation water, based on
measurements made in 200 wells in the project area before and after transfer of
managerial control. Both depth of the water table and salinity decreased after
transfer. The area with average water
table depth of 100–200 cm was 25.41% of total area before turnover and 79.45%
after, and the area with water table depth 200–300 cm was 73.84% before
turnover and 20.50% after. Before turnover, the area with average groundwater
salinity 1.5–2.0 dS/m was 26.16% of total area, and
that with average salinity 2.0–2.5 dS/m was 61.73% of
total area; after turnover, average groundwater salinity was 1.5–2.0 dS/m in over all areas. Both changes were the consequence
of an increased amount of applied water after transfer of the control of
irrigation management from the state to local irrigation districts controlled
by farmers. In the short run, the farmers will get benefit from increased
irrigation. However, over the long term, if water table depth continues to
decrease then secondary salinization could become a
major hindrance to irrigation sustainability.
Key words: Water table depth, Groundwater
salinity, Turnover
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