Three first-, second- and third-order experimental forested watersheds located within the Francis Marion National Forest in the lower coastal plain of South Carolina were monitored for rainfall and stream outflows. The largest watershed (WS 78) with some open lands, roads and wetlands gave higher annual water yields compared to the two other smaller ones (WS 79, WS 80) with mostly forest vegetation, possibly due to a difference in land use, soils and topography as well as increased base flows. Flow duration curves yielded largest flow rates exceeding 4% of the time for the second-order watershed (WS 79). As expected, the daily flows persisted for 79% of the time in the largest 3rd-order watershed (WS 78) with a larger storage compared to only 65 and 60% in the 2nd- and 1st-order watersheds. The flow frequency analysis of peak flows, employing Pearson III- -type distribution, revealed the peak flows for 100-, 50-, 25-, 10- and 5-year return periods as 1805, 1565, 1326, 1009 and 769 cfs (cubic feet per second) for WS 78; 379, 325, 272, 200 and 146 cfs for WS 79; and 73, 63, 54, 41 and 32 cfs for WS 80. These results are in good agreement with the data calculated using the USGS-developed formulae for the South Carolina lower coastal plain and have implications for the design of engineering structures, water and nutrient management, as well as evaluation of the impacts of development and natural disturbances on the forested lands of the Atlantic Coastal Plain.

The study assesses the influence of the loads of some pollutants (BOD5, suspended solids, total nitrogen and total phosphorus), discharged to the Ner river, the right-bank tributary of the Warta river, before the construction of a municipal sewage treatment plant in Łódź, and during its start-up and further operation. Despite its low natural flow, Ner discharges annually a relatively high load of pollutants into Warta. In the research period (1995-2003), the annual average flow of Ner constituted 10% of the annual average flow of Warta below the mouth of the tributary, while the contaminant loads carried by Ner averaged 27% of total nitrogen, 37% of phosphorus, 39% of BOD5, and 28% of suspended solids loads in Warta. In the years 1995-2000, before the start-up of the biological and chemical sections of the treatment plant, the respective values were 29, 41, 44, and 37%, and then, after the plant reached its full capacity, they decreased to 23, 29, 25, and 16%.

The study was based on the results of field investigations and observations carried out on four experimental plots located on the internal dumping ground of one of the open pits of the Brown Coal Mine “Konin” in the Kujawskie Lakeland. After the technical reclamation completed in 1998, the new owner of the post-mining grounds implemented biological (agricultural) reclamation. It follows from the results of the research that the upper layers of those agriculturally reclaimed grounds show small differences in soil texture and basic physical and water properties. The variation in the water reserves of the 100-cm layer in the vegetation period depends mainly on the pattern of meteorological conditions.

Assessing drought severity is an element of drought monitoring. The severity of drought may be assessed by using various indices as drought criteria. The choice of the criterion affects the result of determining the frequency of dry periods in a given severity class. An analysis of 35-year-long (1970-2004) meteorological records concerning vegetation periods (April-September) and coming from five meteorological stations located in different agro-climatic regions of Poland was used to calculate the standardised precipitation index (SPI) and standardised climatic water balance (KBWs). Within the range of the negative values of SPI and KBWs, four drought classes were distinguished: mild, moderate, severe and extreme. Then, the frequencies of months and vegetation seasons in a given class were established. Using SPI yielded a smaller number of droughts in general than employing KBWs and a smaller number of vegetation periods with drought. Based on SPI, the number of months with extreme and severe drought appeared to be greater compared to KBWs, while the latter index showed more months with moderate and mild drought. Employing an index accounting for meteorological conditions of evaporation (KBWs) softened the judgment on drought severity (periods were shifted to a lower drought class) in comparison with an index based solely on precipitation (SPI).

The monthly values of standardised climatic water balance (KBWs) and standardised precipitation index (SPI) during the vegetation periods (April to September) of the years 1970-1995 in Polesie Lubelskie were calculated, compared and used to assess the intensity and length of meteorological droughts. The results showed that the values of both indices are closely related: there is a statistically significant functional relationship between KBWs and SPI. The quantification of this relationship, provided in the study, may be useful in estimating the monthly values of KBWs on the basis of those of SPI, as the former values determined in such a way are only slightly lower than the latter. The results of the study indicate that the complex system of meteorological conditions, expressed as standardised climatic water balance, and the variation in precipitation, expressed as standardised precipitation index, have a similar effect on the intensity and length of meteorological drought in the vegetation period. Hence, the KBWs and SPI indices are really useful for research into the relationships between meteorological drought and agricultural drought in such periods.