Drought is one of the important phenomena resulting from variability and climate change. It has negative effects on all economic, agricultural and social sectors. The objective of this study is to rapidly detect climate dryness situations on an annual scale at the Mellah catchment (Northeast Algeria) for periods ranging from 31 years through the calculation of: the standardized precipitation index (SPI), the standardized Streamflow index (SSFI), the standardized temperature index (STI). Calculations made it possible to locate periods of drought more precisely by their intensity, duration and frequency, and detect years of breaks using the tests of Pettitt, rang, Lee and Heghinian, Hubert and Buishand. The use of the statistical tests for the rainfall series analyzed show all breaks, the majority of which are in 1996/1997 and 2001/2002. For the tem-peratures the breaks are situated in 1980/1981.
The paper presents the problem of the growing water deficit and the possibility of sustainable development of water resources in rural areas of Central and Eastern Europe (using the example of Poland). It is estimated that the amount of resources in this region is reduced by about 70% compared to the average for Europe. In drought periods it comes to limitation of economic activity, including agriculture. Particular attention was paid to the necessity to extend landscape, underground, and snow retention, as an alternative to dams, which are currently the most popular in lower-order catchments. It has been shown that the construction of small agricultural reservoirs is not always preceded by adequate consultations and pre-design studies, which may result in financial losses and legal problems. Simultaneous use of many alternative forms of retention should be more effective than the implementation of reservoirs. In addition, increasing the hydraulic roughness of the catchments slows down the outflow of products of erosion and contributes to the protection of surface retention structures (maintaining natural and economic usefulness of reservoirs).
The aim of the study was to assess the content of soluble forms of fertilizer nutrients (N, P, K) in the cultivated soil layer up to 20 cm deep from agricultural land in the river valley, and the concentration of these nutrients in the surface wa-ters of the Raszynka River.
In the years 2016–2017, the surface water samples from the Raszynka Rriver (17 points) and soil (19 points) were col-lected from agricultural areas near the Raszynka River.
The surface water samples were collected once a month during the March–October 2016–2017. The contents of nitro-gen (Ntot, NO3-N and NH4-N), phosphorus (Ptot, PO4-P), total organic carbon (TOC and K and Ca) in soils and in waters were determined in the sample solutions.
It was shown that river water was of low quality due to the high concentration of nitrogen and phosphorus and electri-cal conductivity (EC). The most polluted were the waters of the lower section of the river located in the vicinity of arable land and agricultural built-up areas. The soluble forms of nutrients content in the cultivated soil layer was varied dependingon the kind of nutrient, way of agricultural land use, and the term of soil sampling. The content of dissolved P forms in the soil was the highest in autumn on arable lands after harvesting of vegetables (GO-W: 10.24 mg Ptotꞏkg–1 in D.M.) and this component may migrate with surface runoff and increase the risk of surface water eutrophication.