Volume XV |

A Special Issue: Hydrological Behaviour in Small Basins Under Changing Conditions

Abstract: The present paper aim to overview on the Euromediterranean Network of Experimental and Representative Basins conference – ERB 2016. The 16th Biennial Conference ERB was held 5–8 September 2016 in Bucharest, Romania, and was hosted by National Institute of Hydrology and Water Management. The conference program focused on the theme “Hydrological behaviour in small basins under changing conditions”. The conference was followed by a field work on microscale hydrologic monitoring of water balance elements in Voinești Experimental Basin.
This special issues of Forum geografic/Geographical Phorum – Geographical studies and environment protection research (indexing in international databases) includes selected works – contained a variety of hydrology subjects – presented at the Euromediterranean Network of Experimental and Representative Basins conference. All published papers are assigned to Digital Object Identifier (DOI).

Volume XV |

Field Assessment of Soil Water Repellency Using Infrared Thermography

Abstract: This study aimed to evaluate the applicability of an infrared thermography technique relying on cooling the soil surface with cold water for assessing soil water repellency (SWR) severity under field conditions.
This study is a follow-up of earlier exploratory small-scale laboratory tests, where SWR spatial variability was mapped and repellent areas could be clearly detected on the thermal imaging due to their higher temperatures, thus distinguishing them from the remaining wettable areas.
Field tests were carried out, where both natural and artificial SWR were mapped through thermal imaging, using a portable infrared video camera. Cold water was used to create a temperature gradient on the soil surface in order to assess SWR.
Naturally repellent soils were found in a pine and eucalyptus forest and artificial SWR was induced with a waterproofing spray.
The molarity of an ethanol droplet (MED) test was used to measure both natural and artificial SWR severity.
The technique was, in overall terms, successful in mapping SWR spatial variability, distinguishing repellent from wettable areas as well as distinguishing different levels of SWR severity.
Only extensive testing can, ultimately, validate the technique and reveal its suitability in different field conditions (e.g., surface roughness, surface cover, spatial scale).

Volume XV |

Effect of changes in groundwater levels on selected wetland plant communities

Abstract: Wetland areas maintain a high level of moisture at all times and experience flooding at regular intervals. High groundwater levels help create wetland areas, as does a relative lack of surface water loss. The paper bases on the hypothesis that wetland areas are characterized by seasonally high water levels and drought. These changes in water content markedly affect the presence of rare plant communities. The purpose of this paper is to determine the effect of changes in the level of groundwater on selected plant communities in wetland areas. The paper also aims to determine if any other determinants affect these plant communities: (1) relief, (2) climate conditions (precipitation, temperature), (3) human impact. Furthermore, the paper provides a detailed hydrographic analysis of wetland areas including information on water migration pathways, water recharge systems, and sources of water loss. The study area consists of Piaśnickie Łąki – a protected natural area in northern Poland, close to the Baltic coastline. It is also a designated “Nature 2000” area, and it is abundant in rare plant communities such as reed grass (Molinietum medioeuropaeum), which thrives in variable moisture areas. The majority of the research work consisted of literature analysis and fieldwork, which included the installation of a groundwater monitoring system, groundwater and surface water level gauging, and discharge gauging for larger streams found adjacent to the study area. The fieldwork was done in the period 2014 – 2015. The collected research data indicate that groundwater levels did vary during the study period. These conditions helped produce a high rate of plant growth and an increased rate of evapotranspiration across the surface of the study area, which then helped decrease the level of groundwater. One basic condition for the functioning of variable-moisture reed grass communities (Molinietum medioeuropaeum) is a specific pattern of variability in groundwater levels. Small depressions in the studied nature reserve offer the best conditions for the occurrence of reed grass communities.

Volume XV |

SWAT Model Application for Simulating Nutrients Emission from an Agricultural Catchment in Ukraine

Abstract: For the first time in Ukraine, a process-based watershed model SWAT was applied for the analysis of a surface water body contamination by nitrogen and phosphorus compounds. The model was applied in a small Holovesnya River Catchment (area 30.4 km2) located in the forest zone of Ukraine on the territory of the Desna water-balance station. The model run was in daily step for years 1985−1988, 2007, 2009, 2010, 2012. The calibration and validation within SWAT-CUP showed good results for streamflow (NS, R2 > 0.6, PBIAS < 4%), acceptable for nitrogen and phosphorus loads (NS > 0.6, RSR < 0.6, PBIAS < 43%). Streamflow and removal of nitrogen and phosphorus mineral compounds were to estimate the dependence of nutrient wash-off on the amount and practice of fertilizing were evaluated to provide recommendations for agricultural management. Increase of the amount of fertilizer results in the reduction of its efficiency. Divided application of fertilizer leads to the nitrate wash-off reduction by 66%.

Volume XV |

Evaporation and evapotranspiration in Romania

Abstract: Evaporation and evapotranspiration are two of the most important elements for achieving a comprehensive study of water balance components and of conceptual hydrological models, lately becoming parameters of great interest in research on climate change. This study can be used for determining of evaporation and evapotranspiration rates at micro-scale using indirect methods. The importance of this study consists in identifying the regions exposed to significant water release in terms of water evaporation and evapotranspiration, in order to improve the practices and methods of water reserve management nationwide. In Romania, the spatial distribution of the analyzed variables is, for the most part, determined by the relief, which constitutes the main factor that dictates the particularities of both the local and regional climate. Among the morphometric characteristics of the relief, altitude plays the most important role in the spatial conditioning of the analyzed parameters. The spatial distribution of evaporation and evapotranspiration, at annual, seasonal and monthly levels in Romania was made through the spatial interpolation method (Digital Terrain Model with a resolution of 30 m). The results of the analysis revealed the following aspects: on a multi-year period, evaporation in Romania ranges from 300 mm – 800 mm/year, with the highest values recorded in the south east of the country and the Danube Floodplain (over 1,000 mm/year), western part (over 800 mm/year) and the lowest values registered in the mountain areas (less than 400 mm/year). The values of evapotranspiration vary between 300 mm/year and 625 mm/year, with a maximum of over 650 m/year in the plains and a minimum of less than 300 mm/year in the mountains.