Droughts and Irrigation
Longer periods of rain absence occur mainly in the
sub-Mediterranean (coastal) region and northeastern
Panonic region. Drought occures every year somewhere
in Slovenia depending on the duration of the period
without rain, soil with its water retention capacity
and stage of the growth of the crop. Statistics show
that on average 19-day droughts can be expected every
second year in coastal region, 16-day droughts every
second year in northeastern region, while extreme dry
periods during summer months
(years: 1983, 1985, 1988, 1992, 1993, 1994, 2000)
can last even 35 days (less than 1mm/day rain-not considered) in northeastern and
southwestern regions of Slovenia as most important
agricultural regions.
Irrigation in Sloveenia is, with some exception, of a supplementary nature, adding water to crops to get through dry periods during the growing period of field crops. The situation is different for 'cash crops': vegetables, fruits, hops and some industrial crops, where irrigation is a basic measure for ensuring good quality and quantity of products and timely delivery of the product to the market.
After a severe droughts (1992-1993) irrigation development has accelerated with irrigation strategy accepted at the governmental level. In 1994 National Irrigation Program (NIP) was prepared and on the base of it the World Bank prepared Feasibility Study in 1997-1999 and suggested to develop an additional 10.000 ha of irrigation schemes in Slovenia in addition to the approximately 6.000 ha of existing schemes
It is necessary to draw attention to the irrigation facilities,
generallly of smaller extend (less than 10 ha), not included
in statistics above. Many of them operate without any
authorisation for water withdrawal and, according to the
Water Law, should not be charged for water abstraction.
The reasons for this situation are rather complicated
administrative procedures, the inefective inspection
services and the fragmented structure of farmland.
Water sources that are used for
irrigation during periods of drought include:
- water abstraction from larger watercources such as the
Drava and Mura rivers, that have high
mean discharge in dry summer months (alpine regime)
- water retained in artificial reservoirs; in 91 reservoirs
there are approximately 104 mio m³
stored. About 15 % of this amount could be used for
irrigation purposes; 31 reservoirs can be
used for irrigation while 60 are multipurpose reservoirs
serving mostly electric energy
generation, where as secondary use, irrigation is
permited
- groundwater abstraction
According to the information of the Ministry of Agriculture,
Forestry and Food (MAFF) 7.707 ha (1997) of arable land are
equipped with irrigation distribution systems (data of
Statistical Office lists 5.768 ha for 1997). The data of
MAFF seam to be more up-to-date, on the other hand it might
also be that some older systems are no longer functioning as
planned. In 2000 the area of irrigation schemes increased
to 9.000 ha according to MAFF.
The types of irrigation equipment recommended by NIP to be
used are depending on the conditions and crops concerned:
rollomats (sprinkler irrigation), drip irrigation and
micro-jet irrigation systems.
