THE INFLUENCE OF CLIMATE AND PEDOLOGICAL DROUGHTS ON THE HYDROLOGICAL DROUGHT OF THE SMALL HYDROGRAPHIC BASINS FROM THE NORTHEN PART OF CODRU-MOMA MOUNTAINS, BIHOR COUNTY

The main way to mitigate the effects of pedological droughts and avoid production losses is to supplement the precipitation and to supplement the soil water reserve by administering of some irrigation norms. The main objective of this paper is to study the connections between the hydrological droughts of small river basins (Finișului Valley, Tărcăiţa Valley and Văratec Valley) from the Beiuş Depression, Crişul Negru river basin and climate droughts and pedological droughts, respectively. The hydrological droughts was monitored with Streamflow Drought Index (SDI) climate droughts with the Standardized Precipitation Index (SPI) and pedological droughts with the standardized Reconnaissance Drought Index (RDIst), using meteorological records from Ștei Meteorological Station, Bihor County, for 19 hydrological years, the period 1991-2010. The most dry hydrological year, during the 19 years analyzed was, after SPI and RDIst Ştei, 1991-1992 (SPI = -1.29 and RDIst = -1.37), characterized as “moderately dry”. The annual hydrological droughts were characterized: on the Finişului Valley “extremely dry” in 1998-1999 (SDI = -2.37); on the Tărcăiţa Valley, 1996-1997 (SDI = -1.59) and Văratec Valley, 2009-2010 (SDI = -1.91) as “severely dry”. The maximum drought duration is six consecutive months for climate drought, 8 consecutive months for pedological drought (soil drought) and 12 consecutive months for hydrologic droughts, respectively. The hydrological year with climatic and pedological droughts with maximum intensities (1995-1996) presents in the 3 analyzed hydrographic basins: 3 months characterized “near normal” drought on Finișului Valley; 3 months “near normal” drought and 1 month “moderate dry” on Tărcăiţa Valley; 3 months “moderate dry” on Văratec Valley. These occur after climatic and pedological droughts with a delay of 0-3 months. Because the months from warm season (Apr-Sep), with the exception of April, are characterized as humid, from point of view climatic and pedologic, makes it possible to natural restore of the soil water reserve, during the vegetation season of crops