Sinkhole Flooding and Aquifer Recharge in Arid to Dry Sub-Humid Regions: A Systematic Review

Sinkhole flooding is an essential hydrological process to recharge karst aquifer in arid to dry sub-humid regions. On the other hand, the increase of rain extremes is one of the major consequences of the global warming, together with the expansion of drylands. Thus, appropriate runoff regulation in endorheic karst basins in order to reduce the risk of flooding and improve the quantity and quality of the water drained by sinkholes will be more and more crucial. With these premises, a systematic review was performed by using WoS engine to infer the best practices for the karst water management in regions actually or potentially affected by water scarcity. Hydrological models are essential to manage the consequences of climate change on karst water resource, however the review shows that providing the tools necessary for reliable modeling is still challenging. Finally, due to the intrinsic vulnerability of the karst aquifers, pollution reduction and wastewater recycling policy will play key role in the next decades.

THE USE OF RADAR TECHNOLOGIES IN THE HYDRAULIC ENGINEERING IN SEISMIC ZONES

Hydraulic structures are designed in a standard way if it is necessary to regulate the water course and maintain the volume of irrigation. The obstacles to the construction of such structures are mainly technical and economic, when instead of building a new hydraulic complex, it is gradually modernised. Consideration of the issues of creating complexes of hydraulic structures leads to the statement of a fact that the water balance of the territory changes. The novelty of the study is determined by the fact that hydraulic structures can be used as prerequisites for the development of qualitatively new programmes for runoff regulation. The authors note that this is particularly important for seismologically unstable areas. It is necessary to lay out plans taking into account not only the possible seismological load, but also the modes and technologies that are used to modernise the already operating hydraulic structures. The practical significance of the study is determined by the fact that the development of hydrotechnical complexes makes it possible to create a system not only for improving the quality of the water balance, but also performs technological support for the safety of the technologies used.

Context-Based Spatial Decisions in Landscape-Ecological Planning

ContextThe vital challenge for the context-based landscape planning is integrating assessments of for both intrinsic properties of a unit and its value in a broad spatial context.ObjectivesThe purpose is to develop the procedure which provides context-based criteria at relevant scales, considers matter flows and dynamic events.MethodsThe methodology involves identification of landscape patterns, revealing mechanisms of radial and lateral relationships, considering changes of landscape patterns, and revealing functioning mechanisms causing directed changes. The proposals proceed from multiplicity of patterns and integrate knowledge of processes in biophysical units, catenas, basins, and matrix elements. The plan was elaborated for the taiga landscape in northern European Russia.ResultsDevelopment of ecological network is aimed at increase of forest cover in basins up to 35% to enhance runoff regulation, prevent soil erosion, and stabilize the riparian biocorridor. The highest significance was assigned to the units that have intrinsic ecological values and contribute to lateral transportation of matter over vast areas. Width of buffer strips intercepting input of pollutants to rivers was adapted to proportions of elements and neighborhoods in catenas. Outside the ecological network, we identified priorities for the multifunctional use of units based on the assessment of drainage conditions, soil quality, and risk of erosion. ConclusionsThe procedure takes into consideration landscape hierarchy and multiplicity of spatial patterns. Integrating multiple models is in compliance with the systemic essence of a landscape ensuring understanding of geodiversity, lateral connections, and the emergent effects that ensure the landscape services for society.

Hydrological Effects of Urban Green Space on Stormwater Runoff Reduction in Luohe, China

This paper reveals the role of urban green space (UGS) in regulating runoff and hence on urban hydrological balance. The modeling software i-Tree Hydro was used to quantify the effects of UGS on surface runoff regulation and canopy interception capacity in four simulated land-cover scenarios. The results showed that the existing UGS could mitigate 15,871,900 m3 volume of runoff (accounting for 9.85% of total runoff) and intercept approximately 9.69% of total rainfall by the vegetation canopy. UGS in midterm goal and final goal scenarios could retain about 10.74% and 10.89% of total rainfall that falls onto the canopy layer, respectively. The existing UGS in the Luohe urban area had a positive but limited contribution in runoff regulation, with similar responses in future scenarios with increased UGS coverage. UGS rainfall interception volume changed seasonally along with changing leaf area index (LAI) and precipitation, and the interception efficiency was distinctly different under various rain intensities and durations. The UGS had a relatively high interception performance under light and long duration rain events but performed poorly under heavy and short rain events due to limited surface storage capacities. Our study will assist urban planners and policy-makers regarding UGS size and functionality in future planning in Luohe, particularly regarding future runoff management and Sponge City projects.

EFFICIENCY OF SEMI-ANADROMOUS AND RIVER FISHES’ REPRODUCTION IN DIFFERENT WATER MODES OF THE VOLGA RIVER

The paper shows the efficiency of natural reproduction of semi-anadromous fish, including the main commercial species such as roach and bream, and river fish species depending on the volume, hydrological regime and duration of spring flood, and the temperature regime of the Volga river during fish spawning. A comparative assessment of the conditions and results of roach and bream reproduction in different water years and periods of Volga runoff regulation is given. The dependence between feeding duration of semi-anadromous and river fry and the efficiency of reproduction, the number of viable younglings and their biological indicators in different water years is shown.

SIMULATION MODELING OF RUNOFF REGULATION BY AN IRRIGATION WATER RESERVOIR UNDER THE CONDITIONS OF LOW-WATER

The article is dealt with the analysis of the Krasnodar water reservoir operation carried out under various options for regulating river flow. The considered options for water reservoir management were implemented in accordance with the current operation schedule and new regulations developed on the basis of simulation modeling using the IMIT-BALANS model which uses optimization elements. Previously this model was adapted by means of a more detailed discreteness of intra-annual intervals. Comparison of the results of the reservoir operation in relation to the deficient planned water yield for dry year conditions showed that the developed new regulations for reservoir management for low water years are much more effective. Their use by the decision-maker (DM) would reduce deficit of water consumption provided that short-term and medium-term runoff forecasts are used.

Intra-annual Runoff Distribution in the Pripyat River Basin

The time variability features of the intra-annual runoff distribution in the Pripyat River basin at the present stage are considered. The study used data from 10 active gauging-stations at the basin area for the period of enabled observations. Changes in the nature of natural runoff regulation of rivers are shown. An increase in the coefficient of natural runoff regulation after the period 1970-1983 for the rivers of the Pripyat River basin was revealed. The relationship between the coefficient of uneven runoff and the share of spring flood was established.