VOLUME 11(33)

Contents

ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute of Water Management, 2000 vol. 11 (33)

ENVIRONMENT POLLUTION DURING THE PROCEDURE OF MANURE HANDLING

S. M. STRUSEVICIENE, Lithuanian Institute for Water Management

Summary

During the storage process manure composition changes: a portion both of nitrogen and the dry matter evaporates into environment. When accumulating solid manure the urine is exuded and as a result a part of nutritious matter NPK discharges with it.

When manure is accumulated in piles in the open field the urine discharging pollutes an area larger 4-5 times than the pile itself. In the result both the nitrogen and the potassium rate in the area would exceed the optimal rate by 6 times, and phosphorus - by 4 times.

In the article there are the study results presented that were obtained on a target dairy farm (the owner of the farm was Mr.V.Liutkevicius) during 1995-1999. The aim of the study was to explore the dynamics of the nutritious matter NPK in the course of manure storage and to follow the formation of urine in a newly established manure place.

As it was established in the course of 8 months because of the mineralisation processes occurring the solid manure, which was produced by milking cows, lost about 9,0 - 12,1% of dry components, about 14,7 - 20,7% of nitrogen, 11,4 - 16,8% of phosphorus, and 12,8 - 17,8% of potassium.

The nitrogen portion lost (20 - 30%) was in the form of ammonium, thus evaporated into environment. Consequently, due to the ammonium evaporation the nitrogen resources reduced by 4,5% on average in the cattle shed, while within the period of 8 months in the manure place the ammonium resources diminished by 10,4%, and within 24 hours after spreading manure it reduced by 9,2%.

Run-off of urine depended on the manure storage extend on the manure place - at the beginning of the storage process the run-off coefficient was 0,96, while at the end of it (completely stored the manure place) the coefficient reduced up to 0,51.

In Lithuania, having such climate conditions, the manure place must store at least the manure volume of cattle of 6 months, and pig manure - of 8 months.

ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute of Water Management, 2000 vol. 11 (33)

PERFORMANCE EFFICIENCY OF SUBSURFACE FILTERS IN CLAY SOILS

V. SAULYS, Lithuanian Institute for Water Management

Summary

In the article there is sub-surface drainage filters performance in clay soils presented. The efficiency was established in a model area "Istro" for comparable drainage discharge, Pasvalys District. It was established that the performance efficiency of the filter would change in view to the change of soil wetness by 1.4 - 4.1 times. Consequently, regression equations for comparable discharges of different subsurface filters have been elaborated, i.e., the equations between the comparable discharges of the filters and soil wetness. Subsequently, it enabled us to link the performance efficiency to meteorological conditions of the area, which was very important in critical moments of pipe line performance.

Under extreme functioning conditions of subsurface infra-structure when soil wetness is higher than 26.8% a subsurface filter made of brushwood-straw, sand-gravel, turf, or shingle performed 9.2, 12.7, 16.4, and 21.5 times better accordingly than that of pipe line with inspection backfilling. Under the conditions mentioned the comparable discharge was 0.0101, 0.0140, 0.0180, and 0.0237 l/s m accordingly. Even better performance was done by subsurface filters of wood chip sacks and brushwood-straw backfilling having 1.5 m width soil layer brought with greater permeability: correspondingly it was 103.7 and 45.0 times better than inspection backfilling of drain pipes. Their comparable discharge was 0.1141 and 0.0495 l/s m accordingly.

ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute of Water Management, 2000 vol. 11 (33)

MEASUREMENT OF A DISCHARGE IN THE LARGE DRAINAGE SYSTEM

S. VAIKASAS, N. BASTIENE, Lithuanian Institute for Water Management

Summary

When performing hydrological measurements and estimating at the same time water discharge collected by great subsurface drainage systems it is faced certain type difficulties. Collectors of such pipe line systems are usually main collector pipes, which contain usually large water discharge. Besides, the water discharge can some times be 100 l/s and even greater. Thus, in this case neither voluminous discharge measuring approach can be employed, which is used usually in smaller pipe line systems, nor Bazen, Thomson, Chipolleti, and/or other construction protection screen for discharge measurement in open drain with similar discharge. In this case open measurement furrows can not be easily applied as well.

On the basis of the known formulas it was developed and tested discharge dependence upon water level in a pipe (to test the dependence laboratory velocity measurement equipment was employed). Character of the water level in a pipe corresponded to the dynamics character of the lines described in pipe hydraulics. Lines showing the discharge dependence are constant and not diverted neither by artificial obstacles nor interventions of a measuring device into the flows. Such approach has been adjusted and employed in measuring the water discharge in a big sub-surface system (about 100 ha) in Joniskis District, Melniai settlement. Comparison of the theoretical and a verified discharge line showed that natural verification was necessary due to deviations from the designed project sloping when erecting collector pipe. Besides, a necessity to take into account a possibility for an open drain to be flooded in the course of the measurement has also been clarified. Despite it, erection construction of post to measure discharge and water level mentioned was sufficiently comfortable and reliable, thus it is applicable in executing monitoring of large pipe line systems under similar conditions as well as installing posts for discharge and water level measurement.

ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute of Water Management, 2000 vol. 11 (33)

INVESTIGATION OF FLOOD DEPOSIT DYNAMICS WITHIN UPPER PART OF THE FLOODED NEMUNAS DELTA

S. VAIKASAS, A. RIMKUS, Lithuanian Institute for Water Management

Summary

During flood period water of the River Nemunas inundates grassland area of the Nemunas Delta. The flow, which slows down in the grassland deposits there soil surface erosion products accumulated from the entire watershed. In the result alluvial soils of grasslands are formed. Besides, in this way it is cleared turbid water discharging into the Curonian Lagoon and the Baltic Sea. This process was being studied during the floods within the period from 1995 to 1999. On the basis of the results derived we have developed a hydraulic-mathematical model "Delta", which served to do the modelling for sediments' deposit in the long-term perspective [ 3,4,7,11,12]. In the calculations there were employed the observation results done at Smalininkai hydro-metric post. At the same post in 1950 - 1991 water turbidity due to the suspended sediments had been followed. Because of it, we were able to model for this time period.

Volume of the sediments depositing has been calculated for the area between Rambynas Hill and Plaskiai., i.e., in summer type polders of River Gege watershed. In fact, the volume of the sediments depositing depended on flood extent and water turbidity rate. As a result it was established that on average about 37% of the sediments passing by Smalininkai had deposited during the study period.

The greatest amount of the sediments in the form of clay and silt including small sediment units deposited during the great floods of 1-3% probability, since more than a half of the flood water discharge flew over the valley then. The greatest deposition load of the sediments was observed after the spring flood in 1958, i.e., 578.630 t. Total amount of the sediments in the modelled area was 2.25 mln. t within the study period. As a result of the sand particles deposition the bank of the River was lifted up by 0.3 m during the 42 study years. Small clay as well as silt particles would deposit more uniformly within the total study area making a 2-3 mm sediment layer. It made about 50 t/ha -60t/ha of small clay and silt sediments.

ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute of Water Management, 2000 vol. 11 (33)

INTERPRETATION OF DATE RECEIVED BY TURBIDITY MEASURING INSTRUMENT

A. RIMKUS, Lithuanian Institute for Water Management

The infra-red or sonar instruments are often used for measurement of suspended sediment concentration. However the amount of sediments received by means of these instruments is expressed not by sediment weight but by area of sediments that are observed in the researched water volume. Therefore a problem occurs to evaluate the real concentration of sediments. That is not always simply, since the coefficient of this evaluation depends upon the suspended sediment size distribution, that is changing in the water flow usually. In this paper it is analyzed some cases of such evaluation, which occurred by performance of our investigations.

ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute of Water Management, 2000 vol. 11 (33)

CALCULATION MODEL OF PERFORMANCE DURATION OF ANTI EROSION MEANS IN THE HILLY AREAS

L. KOZHUSHKO, F. SHVETS, Rivne State Technical University, A. RIMIDIS, Lithuanian Institute for Water Management

Summary

To decrease the soil erosion in hilly areas it is recommended in slopes to arrange the voidless drain pipes filled up with organic material. Voidless drain pipes are strips done by special multitier ripper of 0.3-0.4 m width and 0.5-0.6 m depth. Effective performance of such drains, i.e. full water saturation, it depends on its cross - section and length, as well as material density, depth and width of loosen crack and rain intensity. In the article there is the model for calculation of effective performance time of voidless drains.

ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute of Water Management, 2000 vol. 11 (33)

DYNAMICS OF NUTRIENTS IN THE GEOSYSTEM OF THE KARST REGION IN NORTH LITHUANIA

R. CHOMCENKO, Institute of Geology, V. JUODKAZIS, Vilnius University, A. RUDZIANSKAITE, Lithuanian Institute for Water Managament, J. TAMINSKAS, Institute of Geography

Summary

The karst region in Lithuania is situated in its northern part - Birzai and Pasvalys region. The most intensive karst processes occur in the area covering about 800-1000 sq. km, where conditions are favourable for atmospheric precipitation to enter the subsurface and dissolve shallow-occurring gypsum beds (Figs 1 and 2). Intensity of karst processes is also determined by active groundwater exchange, since dense river network makes good draining conditions.

Active groundwater exchange zone is formed of the Quaternary deposits - mainly morainic loam with sand and gravel lenses and interlayers. Main part of atmospheric precipitation seeps through the Quaternary deposits into the shallow aquifer. However, the infiltration recharge takes place also through karst sinks, number of which range from 20 to 80 in a square kilometre of the karst region.

Under the Quaternary there is Upper Devonian Istra-Tatula aquifer (D3ys-tt) with carbonate rocks stratified with gypsum. Kupi?kis-Suosa aquifer (D3kp-ss) lies lower and is formed mainly of dolomite with marl and lime interlayers. Both aquifers are separated by relative aquiclude.

Migration of chemicals in karst region is mainly caused by convection, when matter dissolved in water is brought with flowing water. Migration of nutrients - beginning with infiltration of precipitation via the aeration zone into the shallow unconfined aquifer and ending with surface or subsurface run-off into the rivers - is a continuous process, which could be quantified in a methodologically right way (determining balance) by means of investigations to be done in a separate river basin according to a unified program. However, such investigations in the karst region had never been performed. Therefore, in the future, in order to improve the nutrient balance investigations, the author undertook an attempt to systemise data of investigations done in different time and place of the karst region and according to incompatible projects.

Since the investigations performed have not been based on unified methodological principles, the methods of nutrient migration in separate environmental components are given together with research results. Basic methodological principle, that was applied for systemising and presenting data in the current paper, is comparative quantification of data obtained during field experiments in different parts of the hydrological exchange zone.

ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute of Water Management, 2000 vol. 11 (33)

LEACHING OF NITROGEN, PHOSPHORUS AND POTASSIUM FROM SOIL WITHIN THE KARST REGION

A. RUDZIANSKAITE Lithuanian Institute for Water Management

Summary

In the paper there are study results on lizimeter as well as drainage water observed within the Karst region described. The study target was to explore the migration of chemical elements in soil layers in view to the farming conditions. It was established that infiltration of mineral nitrogen into deeper soil layers occurred in the winter-spring period. In view to the potassium ions it was identified that the greatest amount of them was found in ground water that was in the top soil layer. As a matter of fact, vegetation /crop cover influenced water quality. The greatest concentration of mineral nitrogen was under potatoes cover in 1997 and the least one was found when having perennial grasses in 1999. However, bigger concentration of phosphorus total was observed both in lizimeter and drainage water when having perennial grasses.

ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute of Water Management, 2000 vol. 11 (33)

DRAINAGE WATER MINERALIZATION OF KARST REGION SOILS AND ITS IMPACT ON STREAM WATER QUALITY

A. RUDZIANSKAITE, P. SUKYS, Lithuanian Institute for Water Management

Summary

To deal with an ecological problem of the Karst region, which is prevention of agricultural pollution into both surface and ground water, it is important to know the regularities of migration of chemical elements as well as nutrient leaching with drainage discharge into water streams and ground drinking water.

Thus, in the article there are 5 year-study results in two pilot karst areas (Birzai District) presented. They show how water quality of streams via drained agricultural areas is influenced by drainage water. It was established that stream water mineralization process was greater, and its chemical composition was determined by formation of soil rocks as well as fertilizers applied in the areas drained including farming type. As a matter of fact, together with the drainage water there were lots of nitrogen combinations leached, which determined the concentration extent in the stream water. In view to phosphorus amount in the stream water, it was the result of other sources and factors.

ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute of Water Management, 2000 vol. 11 (33)

THE CHANGES OF THE WATER QUALITY OF THE OBELIS STREAM UNDER ANTROPOGHENIC ACTIVITY

R. AKSOMAITIENE, Lithuanian Institute for Water Management

Summary

The changes of the water quality of the Obelis stream and its ponds that are acted upon the industrial and agricultural pollution in the last twenty years period are described in the article. Much far less of the ammonium nitrogen and phosphate, but increasing nitrate nitrogen concentration are fixed in the Obelis stream. This process in the basins of different size occurs unequally. The amount of the ammonium nitrogen in the tributaries decreased 4-5 times, in Obelis stream (Juodkiskis) - 13 times; in the tributaries of the nitrate concentration increased 5-6 times, in Obelis stream - about 3 times. The amount of phosphorus changed equally in all basin. The concentration of phosphorus decreased 7-8 times and now there is 0.01-0.02 mg/l of it. The changes of the concentration of organic matter are not so big.

The quality of water in the ponds deteriorates. The quantities of ammonium, nitrities, nitrate nitrogen and organic matter increased. The ratio of the nitrogen and phosphorus changed after the decrease of phosphorus quantity. The present balance of the organic and mineral nitrogen forms and predominating organic phosphorus indicate that the process of eutrofication in the meanwhile goes on slowly.

Industrial pollution does not make a greater effect on the concentrations of the nitrogen and organic matter, but increases the amount of phosphorus 10-20 times in the water of the river.