The Rowden Moor experimental site (A.F.R.C. I.G.E.R., North Wyke) provided an opportunity to characterise discharge regimes, elucidate runoff generation mechanisms and to consider implications for solute movement under natural and drained conditions. Research was conducted on a heavy clay grassland soil in an area of high rainfall (1053 mm a ˉ¹) in South West England. A combined hydrometric and tensiometric study was undertaken within a nested experimental design (1 m² to 1 ha) on one undrained and one drained site throughout a drainage season (October to March). Results at the hectare scale demonstrated that drainage did not substantially alter the volume of field runoff ( ~ 400 mm) but did change the dominant flowpaths. Drainage diverted water from surface/near surface routes to depth so that drain storm runoff was lagged by some 30 minutes over undrained site discharge. The drained site also exhibited a more peaky regime, with a maximum daily discharge of 45 mm being almost twice that for the undrained field. At the field and plot scale, the significance of macropore flow was noted. To investigate this in more detail, a tracer experiment was performed on an isolated soil block which had been mole drained and so had enhanced macroporosity. Macropore flow was generated under unsaturated conditions (little matric potential response and no water table was identified). Stable oxygen concentrations were δ18O +3.5 and -5.8 in tracer and background water respectively. Drainflow indicated that there was rapid interaction between applied tracer and soil water (peak flow δ18O -1.1). Thus, the matrix-macropore interface was not a boundary between two separate domains of old and new water, high and low conductivity but a site of rapid interchange and mixing. Temporal variability of soil status and malric water composition, also indicated that limited areas of the matrix were capable of transmitting rapid flow. It became clear that even in a heavy clay soil such as that found at Rowden, where macropore flow was promoted by drainage operations, the matrix still had an important role to play. On the basis of potential, soil moisture and observation of tracers, it is proposed that discrete (finger-like) volumes of the matrix are capable of rapid water transmission. Although it was frequently impossible to relate moisture content and soil water potential because instrumentation monitored different volumes of soil, hysteretic soil moisture behaviour over the drainage season was evident in both data sets. This study confirmed the importance of rapid subsurface runoff generation mechanisms on drained soils, but noted that discontinuous translatory flow in the matrix and macropore flow occurred and that the two ‘domains’ were inextricably linked. Further work should be undertaken at the detailed scale to elucidate the soil characteristics which promote rapid runoff mechanisms and the consequences for water quality, especially where the soil subsurface represents a major reservoir (e.g. nitrates).

Habilitacijos procedūrai teikiamoje apžvalgoje apibendrinti po disertacijos apgynimo (1984 m.) atliktų mokslinių tyrimų darbų rezultatai. Šiame darbe remiamasi autorės atliktų ir vadovautų maisto medžiagų migracijos tyrimų Lietuvos žemdirbystės institute Dotnuvoje 1992-1995 m., taip pat kartu su bendraautoriais vykdytų tyrimų 1992-2003 m. LŽI bazėje rezultatais bei 1995-1999 m. tyrimų rezultatais, gautais R.Liutkevičiaus ūkyje, vykdant tarptautinį BEAROP (Baltijos jūros aplinkosaugos nuo žemės ūkio nuotėkio taršos) projektą. Šios apžvalgos tikslas ir uždaviniai – išanalizuoti ir apibendrinti biogenų N ir P drenažo išplovos Pajūrio ir Vidurio žemumų agroekosistemų dirvožemiuose tyrimų rezultatus, paaiškinti nustatytas tendencijas, palyginti išplovos rezultatus, gautus nedidelėje drenažo aikštelėje ir didelėje ūkyje esančioje drenažo sistemoje, apskaičiuoti ir prognozuoti išplovas mišrių tradicinių ir ekologinių ūkių sąlygomis bei numatyti užduotis tolesniems tyrimams. Šioje apžvalgoje apibendrinama tyrimų medžiaga apima 19 mokslinių straipsnių, vieną monografiją ir tarptautinio projekto ataskaitą, kurie buvo paskelbti 1995-2008 m. Dauguma straipsnių parengta kartu su kitais bendraautoriais (vienuolikoje iš jų autorė buvo pirmoji). Publikuotos medžiagos pagrindu buvo daryti pranešimai daugiau kaip 19 mokslo renginių (konferencijose, seminaruose, simpoziume) tiek Lietuvoje, tiek užsienyje. / The results of scientific research conducted since acquisition of the Ph.D. in 1984 are reviewed in this survey for habilitation procedure. The nutrient migration research was conducted and supervised by author and performed at Lithuanian institute of Agriculture (LIA) in Dotnuva in 1992-1995, together with other researchers was conducted in the base of LIA in 1995-2003, and in the farm of R.Liutkevičius in 1995-1999, according to the tasks of international BEAROP project (Baltic Environment and Agricultural Runnof Project). The aim and tasks of this survey – to analyse and summarise the results of nutrients N and P leaching from soils of agroecosystems of Seashore and Middle Lithuania lowlands, to explain the trends, to compare the leaching results from small and big drainage system (at the farm), to estimate and forecast the leaching of nutrients under conditions of conventional and ecological farms and to foresee the tasks for the future research. The review material covers 1995-2008 and 19 scientific papers, 1 monograph and 1 international raport published during that period. The most of papers were prepared together with co-authors, but in 11 of them the author was the first. On the base of material obtained, more than 19 presentations were made at different scientific events (conferences, seminars, symposium) in Lithuania as well as in other countries.

ABSTRACT Continuous flow column studies were conducted to characterize suspended sol ids and heavy metal reduct ions through sedimentation with varying overflow rates. The heavy metals tested were cadmium, zinc, copper, iron, lead, nickel and chromium. Stormwater derived samples spiked with street sweepings categorized into particle size ranges less than 500 microns in diameter were utilized in the research. Overflow rates investigated ranged from 28 to 3600 gallons per day per square foot. Theoretical predictions of suspended solids reductions with the application of Stoke's Law exceeded observed reductions for the continuous flow system. Performance curves for all reductions over the observed range of overflow rates are described by a parabolic relationship with the general equation as follows: Reduced fraction= a+ b(Overflow Rate - c) 2 where a, b and c are constants specific to each parameter. Similarities in performance curves for all metals indicate a dependence on suspended solids for reductions. Cadmium and chromium reductions were a function of overflow rate, but did not show a statistically significant dependence on initial total suspended solids concentration. Lead, copper, zinc and iron reductions were a function of initial total suspended solids concentration as well as overflow rate. Iron and nickel exhibited dependence on initial concentration of the specific metal for reductions, as well as dependence on overflow rate and initial total suspended solids concentration. The steady-state models selected from the results of this research for total suspended sol ids and each of the heavy metals are limited to the mixture, specific experimental conditions, and range of overflow rates observed in this research. Observed reductions of total suspended solids and heavy metals are considered to be 1 imited to physical sedimentation processes, in that processes that may effect reductions of these elements in a natural system are not factors in the results of this research.

In this diploma thesis the issue of drainage system influence on water regime of catchment area was solved. The aim of the thesis was to analyze influence of drainage system on specific catchment area using mathematical, hydrological and statistical methods. In the teoretical part, the thesis describes the issue of drainage (specifically the drainage system of area of the Czech republic) and the influence of drainage system on water regime. In the practical part an analysis of the catchment area of Kopaninský creek and subcatchment areas P6, P52 and P53 was performed. At all of those areas, certains parts are dewatered by subsurface systematic drainage system, those parts are described in detail. The runoff coefficients and specific runoff from each subcatchment areas in different time interval were calculated and observed. Runoff separation and precipitation-runoff situation analysis were performed. The results are evaulated in the chapter Results and Discussion.