Volume 43, Nº 3 (2016)

The current features of the space and time variations of river runoff in Kamchatka Krai have been considered. Two relatively long cycles have been shown to exist in water runoff variations in the major portion of the examined rivers. The renewable water resources were increasing until 1970–1980, while in the following years (up to 2010), they were gradually decreasing. Current data on river runoff were used to prove the existence of three zonal types of water regime in Kamchatka Krai; five azonal types of annual runoff distribution are characterized. One of them (nearly uniform annual distribution caused by the predominance of groundwater recharge) has been theoretically predicted in the classification proposed by M.I. L’vovich, though without factual confirmation. The specific features of water regime of rivers whose basins lie on the slopes of active volcanoes are considered for the first time. This type of regime typically shows alternating periods of the presence and absence of surface runoff in river channels, corresponding to the inflow of snowmelt or rainfall runoff at high level of subsoil water (when channel deposits are fully saturated with water) or at its low position (when moisture is deficient).

Results of the quantitative analysis, using 12 parameters, of about 2400 floods of the world are discussed. It is shown that floods are not to a lesser extent social and economic, than the natural phenomena: the most humidified natural zones of the earth are characterized by the smallest damages from floods. Areas of the greatest humanitarian damages (massive evacuations of people, a large number of fatal cases) are related generally with areas of the greatest population density, and areas of the greatest financial damages include as well the territories which are the most developed economically. In spite of the fact that for the analyzed time period the quantity of formally recorded floods increased, average values of the key natural and social-economic parameters of floods did not undergo considerable changes, and mean values of such parameters as the average area of flooding and average financial damage from floods, even decreased a little.

To evaluate the impact of slope length on sediment yield under different rainfall intensities and land use types on low hill gentle slope, the characteristics of sediment yield process were analyzed based on the field artificial rainfall simulation. For the study, grassland and capsicum slope were taken from Anji county of Zhejiang province, China. Results indicated that rainfall intensity had stronger influence than slope length on sediment yield in south region. For capsicum slope, sediment yield increased quickly with increasing slope length when rainfall intensity greater than 90 mm h^–1. The slope length had no significant effect on sediment yield when rainfall intensity less than or equaled to 90 mm h^–1. For grassland, data from experiments indicated that sediment yield increased slowly with increasing slope length under rainfall intensity less than 120 mm h^–1. There was a decreasing tendency of sediment yield at 6 m slope length under all rainfall events. It was concluded from particle size analysis of erosional sediment that silt and clay particles <0.02 mm were always preferentially transported on both capsicum slope (silt 47.1%, clay 40.9%) and grassland (silt 38.3%, clay 35.9%). We hope these results are useful for soil and water conservation and land management.

Water chemistry in the Amur R. at Khabarovsk was studied during the historical 2013 flood. The concentrations of dissolved substances were shown to vary significantly over both time and space, because of the difference between the discharge and chemistry in the main flood-forming tributaries. The ion runoff, nutrient runoff, and microelement runoff were estimated for the flood peak and all over flood period.

Variations of the species structure of periphyton algae community on submerged plants have been studied along the longitudinal profile of the Moskva R. with the use of multivariate statistical methods. The results of principal-coordinates analysis show the flow velocity and biogenic load to be the major factors governing the spatial variations of periphyton structure. Mantel test shows the difference in the species structure to be correlated more closely with local variations in the environmental factors than with the distance along river channel. Therefore, the spatial distribution of periphyton in the Moskva R. agrees better with the concept of patch dynamics than the concept of river continuum. Estimation of the indicator potential of three ecological guilds of diatoms (low profile, high profile, and motile) has shown a positive response of motile diatoms to an increase in the concentration of biogenic compounds. The effect of other factors, such as light intensity in macrophyte stands and the microdistribution of diatoms in periphyton layer, can disturb the relationship between biogenic substance concentrations and the abundance of low profile and high profile diatoms.

The rate of natural removal of ¹³⁷Cs from water bodies in Eastern Fennoscandia is evaluated. The half-time T of water purification from global ¹³⁷Cs in lake–river systems was ~6.5 years and that for river systems was 6.5–10 years. For the 15- and 20-year exposure of ¹³⁷Cs in watershed soils, its annual input in rivers was 0.021–0.120 and 0.017–0.070% of its reserve. The period of May–December 1986 showed maximal export of ¹³⁷Cs, i.e., 1.1% of its reserve. ¹³⁷Cs export into rivers decreased in the region from north to south because of changes in landscape and climate conditions that affect ¹³⁷Cs migration on watersheds.

Nowadays, the problems of rejections constitute an increasingly important danger in the receiving mediums. Indeed, water is increasingly affected by minerals and organic matters and even by the micro-organisms of which some are pathogenic and thus dangerous for the ecosystem. In this context, the present study was conducted to investigate the microbiological pollution of water of the lake Mellah, located in the national park of El Kala, North-eastern Algerian. This lake is a depression which communicates with the sea and flowing the domestic effluents of the neighbouring localities. The physicochemical parameters (Temperature, pH; Eh; Electric conductivity; Salinity, Turbidity, and O₂) and bacteriological (coliformes total, coliformes thermo tolerant, streptococci) were followed during the year 2011 with a seasonal frequency (February, May, August, November). Seventeen (17) sites of three different habitats were investigated; the waste-water treatment plant (WWTP), Wadis and their upstream to the estuary and the lake. The follow-up of analysis of the physicochemical and biological parameters in the various points of observation was the object of a graphs data processing and statistics (ACP) to determine the bacteriological degree of pollution. Results showed a contamination by the fecal matter with a gradient decreasing from the upstream of the discharge system towards the downstream. Compared to rain waters, microbiological pollution in the lake was selective in time. The CT and the CTT decreased in dry season where the ambient conditions (salinity, pH and temperature) become unfavorable, putting the factor salinity concerned to degrade the water pollution.

Water scarcity has been an important issue for many countries. The water scarcity is still growing in some region but may be exacerbated by recent climate change. Both international and domestic reports classified Korea into water scarcity country on the basis of Falkenmark indicator. Korea, however, missed the concept of green water in calculating their annual renewable water resources per capita and erroneously defined them as water scarcity country. A new calculation shows that Korea has no water scarcity with 1712 m³ of annual renewable water resource per capita. Wrong information in Korea was badly used for political propagation and private purpose. This may be happening to other countries. Water resources experts need to include the concept of green water in reanalyzing the annual renewable water resources to provide decision-makers with acceptable guideline. Decision should be made with more reliable ground.