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Contents
ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) THE IMPACT OF THE LAKE ON THE SURFACE RUNOFF IN A BASINArvydas Povilas MALISAUSKAS Summary The studies on the impact of a lake on runoff distribution in the outlet basin were carried out in the basin of the lake Lenas within the periods 1981-1985 and 1993-2001. The Lenas is a comparatively shallow water body (the average depth is 2.1m) the outlet basin of which covers 38.5 km2. Surface runoff of the lake is regulated by a gatewell. The Lenas is a periodically flowing lake the runoff of which last on the average 236 days per year; the other time the water level is observed to be below the flush weir. Surface water input from the influent makes up 79%, while the effluent runoff makes up 72% of total water balance. Comparing with surface water input, the annual effluent runoff decreases 1.23 times, spring effluent runoff and the runoff of limitative period decrease 1.12 and 1.35 times respectively. The regulative impact of the lake on the effluent runoff distribution is observed only in spring when the discontinuity coefficient of the effluent runoff is smaller to compare with that of the influent. Within the limitative period the regulative impact of the lake is mainly predetermined by low water level; monthly discontinuity coefficients are bigger in the effluent (0.5-0.75) to compare with the influent (0.4-0.58). A 10% probability module of maximum runoff of the effluent makes up 52% of the influent module. Keywords: lake, basin, runoff rate, seasonal runoff, runoff module.
Address Article received 08 2002, given to print 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) INVESTIGATIONS ON THE MEANS OF LIME APPLICATION FOR THE TREATMENT OF WASTERWATER FROM FOOD PROCESSING INDUSTRIES Albertas STEPONAVICIUS, Zenonas STRUSEVICIUS Summary Since 1991, the investigations on the treatment of wastewater from different food processing industry enterprises have been carried out, the objective of which includes the determination of the transformation of wastes when wastewater is flowing through septic tanks, sedimentation tanks, different biofilters, or when it is being treated in the aquiferous ambience. As the research data analysis shows, the direct biological treatment of wastewater from food processing industries (the pollution of which exceeds 700 mg/l O2) is impossible. A new technology for primary wastewater treatment with quicklime has been developed. The technology is based on physical and chemical processes of pollutant flocculation. To guarantee the functionality and effectiveness of this technology, the analysis of lime dosing was carried out and an original lime dosing device was created. The paper presents theoretical dependences for the evaluation of the efficiency of lime dosing device. It also presents test results obtained during the investigation, and practical recommendations dealing with the usage of lime dosing device under industrial conditions. Keywords: wastewater, lime, ways of dosing.
Article received 08 2002, given to print 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) WATER DEPTH MODELLING IN THE LOWER NEMUNAS Gintautas SABAS, Saulius VAIKASAS Summary Hydrodynamics modelling software HES-RAS and MinVL were used to evaluate conditions of navigation in the lower Nemunas. It was established that waterway navigation characteristics here satisfy minimal navigation requirements according to class AGN IV. Besides, contradictory conditions exist in the river bed near the settlement Rusne (1.96-2.27 km away), where water depth is not enough for navigation during the dry period. This is because there is a need of bed dredge works here. Hydrodynamics simulation of artificial flooding wave propagation from the Kaunas Hydropower Station pond shows that water levels rise by 0.4-0.2 m only near the settlement Pagegiai. The influence of this flooding is insignificant and hardly perceptible at the distance of 50 km. This is because the means cannot be recommended. The objective of the article was to prove that the usage of software is the best method for navigation flow conditions to be investigated. Keywords: water depth, hydrodynamic modelling, artificial flooding wave.
Dr. habil. Saulius Vaikasas
Address Article received 08 2002, given to print 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) THE PERENNIAL CHANGE OF PRECIPITATION AND ANNUAL RUNOFF IN THE SUSVE RIVER BASIN Laima BERANKIENE Summary On the basis of a long-term data (62-72 years), the paper analyses the perennial change of precipitation and runoff in the basin of the river Susve as well as its water balance calculated according to 10-year moving average. Annual precipitation amount calculated for the Susve basin on the basis of the data of four meteorological stations (Dotnuva, Raseiniai, Siauliai and Kaunas) fluctuates from 47 to 857 mm. The calculations based on 10-year moving average have determined a cyclic occurrence of wet and dry periods. The duration of each occurrence is 15 years. Since 1930, the Susve basin has experienced two wet and three dry periods so far, the first and the last ones being incomplete. Such precipitation fluctuations have predetermined runoff fluctuations in the river. Annual runoff head in the Susve mouth fluctuates from 62 to 300 mm. The calculations based on 10-year moving average resulted in similar runoff and precipitation occurrence in wet and dry periods. A close interrelation between precipitation and runoff was thereby established. Average perennial runoff coefficient of the Susve was found to be 0.24, and the annual runoff coefficient fluctuated from 0.12 to 0.29. The basin of the river Susve experiences 627 mm of precipitation on the average, 24% (152 mm) of which outflow with runoff, 76% (475 mm) evaporate. In dry periods, to compare with wet ones, a larger amount of precipitation (6% on the average) evaporates, and correspondingly a less amount of it outflows with runoff. Even more distinctive results (up to 11%) were obtained when calculating water balance for decades of different water abundance. Keywords: precipitation, runoff, runoff coefficient, evaporation, water balance, moving average.
Address Article received 08 2002, given to print 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) Botanical Structure and Spread of Woody Vegetation in Drainage Channels Romanas Lamsodis Summary Draining and cultivating lands, destroying all riparian vegetation, natural watercourses were converted into drainage channels. Even if slopes are mown, the channels are however the only spots where natural vegetation can take a shelter in the agrolandscape. The investigations were carried out in 418 random channel slope cut-offs located in the territory of about 2000 km2 in the Middle Lithuanian Lowland. There were found more than 36 species of woody vegetation belonging to 22 genera, 13 families. It was determined that the greatest number of species gets in forest channels. Much less species of woody vegetation occurred in field channels. As a rule, small-leaved trees and shrubs prevailed there. Shrubs were, however, observed more often than trees in all channels. It was also observed that the distribution of species depended on the change of growth conditions of vegetation down the slope in a channel cross-section. It is supposed that, considering the tendencies of the spread and distribution of species, there is a possibility of the artificial stimulation (to the desirable direction) of dendroflora restoration in drainage channels. Keywords: number of species, frequency, density, distribution, restoration.
Address Article received 08 2002, given to print 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) THE DYNAMICS OF NUTRIENTS IN THE SOIL WHEN SLURRY IS APPLIED Simanas ASKINIS, Marija CIZAUSKIENE, Stefanija MISEVICIENE Summary The dynamics of nutrients and their leaching were investigated under the conditions of intensive farming, when slurry was applied on farming crops. The studies were carried out in a drained 4.86-ha plot of land in Juodkiskis village (Kedainiai district) in 1995-1998. A four-field crop rotation contained the following crops: sugar beet, barley with undercrop, perennial grass, spring rape. The rates of slurry calculated according to the amount of nitrogen naturally contained in the slurry and considering the expected yield were as follows: I – total rate of slurry applied in autumn, II – total rate of slurry applied in spring, III – half of the rate applied in autumn, another half applied in spring. It was found that crop yield was predetermined by the amount of nutrients contained in the soil in spring as well as by those introduced into the soil together with fertilizers, precipitation and plant residues. The increase in the amount of mineral nitrogen caused a rich yield (R=0.95), while the relation observed between the amounts of mobile phosphorus and potassium and the yield was less influential (R=0.38 and R=0.60 respectively). Dependence of the yield on additional nitrogen input was even stronger (R=0.99). The most productive nutrient uptake was observed when applying slurry in spring: the amounts of nitrogen and phosphorus leached by drainage were then 69.2 kg/ha and 0.2 kg/ha respectively, which made up 9.9% and 0.2% of total applied amount. In autumn the leached amounts were 79.9 and 0.31 kg/ha respectively. Keywords: slurry, nutrients, leaching by drainage.
Address: Dr. Marija Cizauskiene,
Address: Stefanija Miseviciene,
Address: Article received in 08 2002, given to print in 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) SEDIMENT-TRANSPORT CAPACITY OF LITHUANIAN RIVERS Zenonas RIMKUS Summary The dependence of the turbidity of Lithuanian rivers on the main complex parameter v/ (here v is the average velocity of flow, have is the average depth), which characterizes the sediment-transport capacity of the river flow (further – flow transport capacity), has been analysed in the article. In Lithuania the transport capacity has been treated as a maximum turbidity (maximum concentration of suspended load in a flow), and suspended particles have not been settled yet in the presence of particular hydraulic conditions in a flow. We propose to express the flow transport capacity not only as the largest critical meaning, but also as the smallest particular meaning, i.e. the attention is focussed on the fact that when the erosion of river bed begins the least turbidity is observed under the same hydraulic conditions. The limiting curves of transport capacity (points of the function =f(v/) and their empirical dependencies are established. The upper and lower curves express the riverbed accumulative and unwashing velocities accordingly, under particular hydraulic conditions. Keywords: total load, suspended load, flow sediment-transport capacity.
Address: Article received 08 2002, given to print 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) Investigations ON THE CHANGE OF QUALITATIVE INDICES OF WATER IN DUG WELLS Saulius KUTRA, Albinas KUSTA, Vida RUTKOVIENE Summary Applying geostatistic methods the investigation on the pollution of dug wells with nitrates and chloride was carried out in Pypliai village (Kaunas district). The objective of the work was to determine the distance at which the human activity adversely affects the quality of water in a well. Analyzing the variograms made up on the basis of the data of the year 2000, it is noticed that the interface between two different wells exists at the distance of 142 meters. Farm buildings, including cattle sheds, also greenhouses, gardens, lavatories, dumps and other pollution-aggressive objects are usually situated from wells at the distance mentioned above. Farther situated fields almost have no influence on the quality of water in wells. No influence of the pollution on the direction of ground water motion was determined. No relation among the pollution of different wells with chloride was established. All wells are slightly polluted with chloride, some of them are polluted heavily, but the investigation has shown that this is local pollution, non-characteristic to larger groups of wells. Keywords: dug well, ground water, pollution with nitrates, chloride, variogram.
Article received 08 2002, given to print 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) ESTABLISHMENT OF CONCRETE STRENGTH FOR IRREGULAR-SHAPED SAMPLES Kazys Aleksandras VAISVILA, Feliksas MIKUCKIS, Antanas VAITIEKUNAS Summary The compressive strength of functioning concrete structures of hydraulic constructions can be evaluated by testing the samples of irregular shape. The samples are recommended to be tested by means of concave cylindrical steel punches. The concavities of punches must be filled with special smoothing mortar. Prepared punches are located on the opposite surfaces of the sample and are centred properly by the means of special equipment. The concrete compression strength of samples is evaluated by an ordinary compression test. For this purpose a hydraulic or lever compression machines are used in accordance with standard requirements. The concrete compression strength of relative 0.8-2.0 height samples, determined by 35.7; 50.5, 71.4 and 100.0 mm diameter concave punches can be calculated into concrete compressive strength of standard cubes of 100x100x100 mm. Such evaluation can be accomplished by means of the proposed formulae and corresponding coefficients. Keywords: concrete compression strength, irregular shape samples.
Address Dr. Feliksas Mikuckis
Address Antanas Vaitiekunas
Address Article received 08 2002, given to print 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) IMPROVEMENT OF TECHNICAL CONDITION OF LAND RECLAMATION INSTALLATIONS CONSIDERING THE EXPERIENCE OF EU COUNTRIES Kazys SIVICKIS Summary The article presents quantitative indicators of land reclamation installations, their values and depreciation, the peculiarities of the damages in drainage systems.It also generalizes financing data of all the land reclamation works and the improvement of technical condition of land reclamation installations for the period of 1995-1998. Besides, it provides changes dealing with the financial contribution for 1 ha of drained land. Considering the results of the analysis of technical condition of land reclamation installations and the norms for their depreciation degree, the article presents the demand for financial means required for the improvement of the condition of land-reclamation installations. Besides, the article examines and reviews the general condition of land reclamation equipment in the country and the significance of land improvement by creating competitive farms. It also provides with the suggestions for the reformation of financing system of the improvement works of land reclamation equipment by taking advantage the experience of EU countries. Keywords: land reclamation equipment, value, mechanical depreciation, condition, financing.
Address Article received 08 2002, given to print 10 2002.
ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) INVESTIGATIONS ON THE DETERIORATION OF SLOPES IN THE PROCESS OF MECHANIZED MAINTENANCE OF CHANNELS Stasys RAGAUSKAS Summary The paper presents the research data about the deterioration of lower part of channel slopes caused by the process of the mechanized maintenance of the bottom of channels. It has been determined that using different channel maintenance machinery the ground and the vegetation of lower part of slopes are damaged on a different extent. Those factors influence much further accumulation of sediments. As a three-year investigation has shown, most often channel slopes and their footboard are damaged when using technically worn out swing buckets K-82 that uncover footboard of channels, widen their bottom and stir the ground of the bed, which enlarges the amount of sediments. When segment-type and clamshell buckets are used, channel slopes and their footboard are almost undamaged. Using this type of machinery the amount of sediments accumulated in channels within a there-year period is half as big as the one that accumulates when swing buckets K-82 are used. Keywords: channel, sediment, slope, footboard, dredging, clamshell bucket.
Address Article received 08 2002, given to print 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) evaluation OF THE technical statE of reinforced concrete strengthening slabs fOR THE EMBANKMENTS OF PONDS Raimondas SADZEVICIUS Summary The reinforced concrete strengthening slabs of functioning water engineering constructions (WEC) were investigated. At present the state of every reinforced concrete strengthening slab is not the same in all functioning WEC. There is a number of strengthening slabs functioning almost properly, others are more or less deteriorated. Regulations STR.1.12.03:2000 briefly describe the state of upstream slopes and discount the condition of reinforced structures. In order to describe the type of physical deterioration of strengthening slabs, a number of initial data must be collected. In 1999-2001, the reinforced concrete strengthening slabs of 12 WEC were investigated. Actual values of the main physical-mechanical properties of concrete, defects and deteriorations of structures were established. The principal attention was focussed on the establishment of actual values of compression strength, volume mass and absorptive power of concrete used in reinforced concrete strengthening slabs. On the basis of field investigations, the main types of defects and deterioration of reinforced concrete strengthening slabs and their reasons were described, conditions of strengthening slabs were estimated by points. The objective of the work is to present briefly the right technique for the evaluation of technical state of reinforced concrete strengthening slabs functioning in the alternative level of water. Keywords: technical state, reinforced concrete slabs, deterioration.
Address: Article received 08 2002, given to print 10 2002. ISSN 1392-2335 Transactions of the Water Management Institute of Lithuanian University of Agriculture 2002, 20(42) INVESTIGATIONS ON THE PRECISION OF COLD WATER METERS ARRANGED IN FLATS Antanas SAKALAUSKAS, Algirdas MATUZEVICIUS, Regimantas DAUKNYS Summary In 1994-1995, the owners of flats of communal buildings started installing water meters in their flats. The account of water quantities was arranged very well in dwelling-houses. Double accounting allowed to compare total (according to water meter on incoming main) and individual (according to water meters of the owners of flats) consumption of water. The results were the same in all towns of Lithuania – the inhabitants declared less amounts of consumed water to compare with the readings of water meters on incoming mains. In 1990, the loss of water was 10%, in 1998-2000 it increased up to 32-36%. The biggest losses of water are observed in Vilnius, Kaunas, Birzai, Kupiskis, Plunge, Alytus. In these towns most consumers have water meters installed in their flats. The aim of this study was to find the answer why the water meters arranged in flats of communal buildings do not meet permissible errors. The main requirements for the arrangement of water meters are described in the second section. The main parameters and metrological classes of water meters are overviewed (Table 1). The third section presents the methods of investigation. Six types of water meters are analyzed. These water meters are most widely used in Lithuania. The investigation comprised two stages. First, the state of water meters was evaluated, then the precision tests were performed. The water meters were tested in JSC "Rubikon apskaita". The tests comprised external examination, waterproof test, test of precision and determination of errors. In order to implement the second part of the investigation the test bench for water meter was constructed (Fig. 1). Different types of water meters were tested. Those water meters were arranged in vertical and horizontal positions with different distances between a water meter and a valve. According to the obtained results, the errors of precision were calculated. The results are given in the fourth section. As the results obtained by JSC "Rubikon apskaita"show, 2 new water meters out of 6 are unsuitable for the exploitation. Therefore, only 4 meters were analyzed in the second part of the investigation. The main results of the tests are given in Tables 2, 3, 4 and 5. Relationship between the errors calculated according to equation (6) and hour flow rates are presented in Figures 2, 3, 4 and 5. The fourth section comprises conclusions. It was determined that cold water meters of metrological class B did not exceed the permissible error of ± 5% when they were mounted in a horizontal position and the flow rate was from 30 l/h to 120 l/h. But when the flow rate exceeded 120 l/h the only water meter "Metron" that was mounted at the minimum distance from valve met the requirements (± 2%). All vertically fixed water meters exceeded permissible errors. The only exception was the water meter "Minomess" (metrological class A). This water meter did not exceed permissible errors when it was mounted at a required distance from the valve. The results showed that negative errors were obtained when there were smaller flow rates (approximately up to transitional flow rate), i. e. the water meters showed smaller amounts of water than the actual ones. When the flow rates exceed transitional flow rate the errors become positive. An exception is the water meter "ISO-4064", but the precision of this water meter was worst during all the tests. Keywords: cold water meters, permissible errors.
Address Dr. Algirdas
Address Dr. Regimantas Dauknys,
Address Article received 08 2002, given to print 10 2002. |
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