The results of winter checks in drainage systems of three cities in northern Poland are presented. The analysis of importance of this type of roosts for hibernating bats is conducted. In total 7524 bats were counted in the winter 2013: 3412 individuals in Olsztyn, 3403 in Piła and 709 in Koszalin. Higher number of bats than in rainwater sewers of Olsztyn and Piła was observed in Nietoperek Reserve only. Six bat species were recorded in checked rainwater sewage systems: Myotis nattereri, Myotis daubentonii, Myotis myotis, Plecotus auritus, Barbastella barbastellus and bats from Myotis mystacinus complex. Urban sewage systems are important especially for Myotis nattereri. This species dominates in all checked objects, with 3314 individuals in Olsztyn, 2532 in Piła and 597 in Koszalin. Given the sheer size of the drainage systems, this type of roosts may belong to the most important hibernation sites, particularly for M. nattereri and M. daubentonii.
The sizing of a storage reservoir, in order to reduce maximum water discharges in stormwater drainage systems, is one of the major topics in the civil engineering. In this article a methodology that allows identifying an optimal capacity of a pipe reservoir is proposed. Applying a simplified water flow model it was possible to bind various reservoir’s parameters (a reservoir diameter, a diameter of an outflow orifice and an outfl ow coefficient) with an infl ow hydrograph (a peak flow, a time of rising, a hydrograph fineness, a maximum discharge and a total volume). On the basis of functional relationships the nomographs were elaborated, allowing determining a desirable size of the reservoir, in a sense of a required peak reduction. The usage of the proposed methodology is presented with a simple example.
The paper contains the results of eight-year-long studies on the runoff of nitrates from heavy soils used as croplands. The runoffs of nitrates from a drainage catchment and a catchment drained with ditches were compared. The drainage system was found to carry away twice as much water, with a five-fold higher concentration of nitrates and 20-fold higher load of nitrates, than the system of ditches. High runoff of nitrates (22 kg ha-1 annually) from the soils drained by drains was distributed quite evenly throughout the year, with maximum peaks in March and June. Nitrate runoff through the system of ditches was low (1.15 kg ha-1 annually), reaching maximum peaks in March and April (62% of the load), but disappearing in the summer.
The study area is located in the southern part of the Warsaw city agglomeration, adjacent to the Chojnowski Landscape Park. The study area is situated in the boundary zone between: (1) the bottom of the river valley reach with peat cover and (2) the Pleistocene glaciofl uvial plain on its lower level. The main aim of the study is the analysis of the investment impact on hydrogeological conditions. During the preconstruction site works on the bottom of the valley it was an earthwork constructed in order to extend the zone of the buildings in the valley area. The research method consists of fi eld works (geological drillings, piezometers constructions and observations, geodetic measurements), as well as laboratory works (sieve analysis) and hydrodynamic modelling (Visual MODFLOW, version 2009.1). The hydrogeological model performed in the study seems to became a base for the concept of the restoration of groundwater conditions.
A hydrophyte treatment system was constructed in Bielkowo in order to protect drinking water intake for the city of Gdansk against surface and point sources of contaminants. The system consists of two subunits: a wet unit (pond), filled with water all the time and a dry unit (extension of the pond), designed for storm water. In the wet unit are placed dams constructed of medium size sand. The system, especially dams, is inhibited with macrophytes. The drainage system collects water percolating through dams, and directs it downstream. The system was constructed in 1997. After implementation of the system substantial improvement in water quality occurred.
There is a significant shortage of water in many valleys in Kurpie region caused by the drainage impact of the ditches. Field studies and numerical calculation have been conducted to establish principles of water management in irrigation-drainage systems. The regional groundwater model SIMGRO has been used for calculation. The studies showed that the regulation of water outflow from ditches is an effective method of water harvesting in the geological conditions of Kurpie region.
An examination of four specimens of the common caiman, Caiman crocodilus (L.), from small lakes (“lagunas”) in the surroundings of Boca de Anaro on the Suripá River, State of Barinas, Venezuela revealed the presence of two nematode species, Brevimulticaecum baylisi (Travassos, 1933) and Micropleura vazi Travassos, 1933. The finding of the latter species represents its first record from Venezuela and from the Orinoco River drainage system. A detailed study of their morphology, including SEM, made it possible to establish some new, taxonomically important morphological features of these species (e.g., the presence of cervical alae and the exact number and arrangement of male caudal papillae in B. baylisi, the number and arrangement of cephalic papillae and the structure of cuticular ornamentation in M. vazi). Brevimulticaecum sp. infective larvae reported by Moravec et al. (1997) from fishes originating from the same locality as the caimans are now considered to belong to B. baylisi.
Celem pracy była analiza aktualnych warunków prawnych, technicznych, organizacyjnych i finansowych funkcjonowania spółek wodnych, na przykładzie działalności Spółki Wodnej Melioracji Nizin Obrzańskich. Analizy wykazały, że zakres robót konserwacyjnych wykonanych w latach 1997-2006 przez spółkę pokrywał zaledwie 10% potrzeb. Jako jeden z głównych powodów można wskazać niedostateczną ilość środków finansowych przeznaczanych na roboty konserwacyjne. Zbyt mała w stosunku do potrzeb jest nie tylko składka uchwalana przez członków spółki ale istotnym problemem jest jej ściągalność szacowana na 70-80%, a w niektórych rejonach nawet zaledwie na poziomie 50%. Niedostateczny w stosunku do potrzeb jest też stopień pomocy państwa oraz jednostek samorządu terytorialnego w dofinansowaniu działalności spółek. Analizy wykazały, że dotacje dla Spółki Melioracyjnej Nizin Odrzańskich w analizowanych latach systematycznie malały i wynosiły średnio rocznie niecałe 12% budżetu. Organy państwowe i samorządowe muszą wyraźnie wskazać, czy są zainteresowane funkcjonowaniem infrastruktury wodno-melioracyjnej i czy przekażą środki na pomoc w jej utrzymaniu, tym bardziej, że spółki wodne nie mogą liczyć na dotacje unijne do statutowej działalności. Skutkiem zaniedbań w utrzymaniu jest bowiem przyspieszone zużycie techniczne urządzeń melioracyjnych a perspektywą, nieunikniona - znacznie kosztowniejsza ich odbudowa, mogąca przywrócić sprawność funkcjonowania.
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