Bilans wodny zielonego dachu na przykładzie obiektu w dzielnicy Ursynów m.st. Warszawy

Celem niniejszej pracy jest przedstawienie wyników badań dotyczących retencji zielonego dachu na przykładzie obiektu położonego w dzielnicy Ursynów m.st. Warszawy. Obiektem badawczym był fragment zielonego patio zbudowanego z substratu będącego mieszaniną torfu, piasku i keramzytu, o miąższości warstwy 25 cm. Warstwę wegetacyjną zielonego tarasu stanowią darń z mieszanki traw oraz krzewy iglaste i liściaste. Do obliczania składowych bilansu wodnego w okresie wegetacji 2008 roku wykorzystano model bilansowy GreenRoof. Badania wykazały, że rozpatrywany zielony dach zretencjonował ponad 99% wody pochodzącej z opadów

Importance of the Influence of Drained Clay Soil Retention Properties on Flood Risk Reduction

Subsurface drainage is a common water management practice in rural areas whose soil has poor permeability and where the groundwater table is periodically high. In addition, drainage systems are used to prevent waterlogging and flooding. The aim of this study was to investigate the influence of drained clay water retention properties on flood risk reduction. Field research was conducted at the Lidzbark Warmiński experimental site (Poland). Three case studies were considered: early spring, spring, and late autumn/early winter. In the first case, soil moisture was found to be close to the saturated water content. Snow melting and even light rainfall had caused an immediate reaction from the drainage system. In the second case, soil moisture decreased steadily, so the soil water retention capacity increased. The response time between precipitation and outflow was four days. In the third case, melting snow and further precipitation during the days that followed caused a rapid increase in drainage outflow (after 24 h). Two values were introduced: the precipitation retention rate (prr) and drainage outflow factor (df). In all cases, the prr value was in the range 32–34%; the df oscillated around 29% in the first and second cases, and reached a value of 68% in the third case

Nitrate nitrogen and phosphate concentrations in drainflow: An example of clay soil

Nutrients dissolved in water and not taken by plants leach into deeper soil layers or flow out to surface water through pipe drainage systems, causing ground or surface water contamination. Thus, drainflow from agricultural areas has significant influence on surface water eutrophication. The objectives of this study were to evaluate nitrate nitrogen and phosphate concentrations and load changes in drainflow using as an example clay soil analyzed in period spanning the years 2010 and 2013. Field research was conducted at an experimental site in Lidzbark Warmiński, in the Province of Warmia and Mazury (województwo warmińsko-mazurskie) in Poland. Mollic Gleysols developed from loam and clay dominate in this area. The experimental field has a tile drainage system with 21 m drain spacing and average 0.9 m drain depth. Winter wheat (Triticum L.) and oilseed rape (Brassica napus) were cultivated in 2009–2012 and in 2012–2013, respectively. Chemical analysis of water samples was performed with a Hach Lange DR 3900 spectrophotometer. Annual rainfall ranged from 555 mm in 2013 to 814 mm in 2012. Average nitrate nitrogen daily loads ranged from 0.07 to 0.58 kg ha-1, while the total annual nitrate load varied from 7.5 to 34.6 kg ha-1. Daily loads of phosphate were about ten times lower than daily loads of nitrate and the total annual phosphate load ranged from 0.1 to 2.0 kg ha-1. Neither nitrate nor phosphate concentrations are strongly depended on drainflow, but the nitrate nitrogen concentration indicates some relationship with the season. A substantial increase in the nitrate nitrogen concentration appears at snow melting (March) and continues until the end of May, peaking in the third decade of April, when the cultivated crops begin the vegetative growth. The phosphate concentration did not undergo significant changes during the investigated period

Determination of Tile Drain Discharge under Variable Hydraulic Conditions

The aim of this study was an investigation of tile drain flow velocity under variable hydraulic conditions and of tile drain discharge using an ultrasonic flow meter. There is an essential variance between velocity values measured by an ultrasonic flow meter and reference values determined by a laboratory method. Differences result from specific measurement conditions, which appear in drainage pipe systems. The values of velocity measured by ultrasonic flow meters were higher than the reference values for three examined flow phases: Free, transient, and pressured flow. The discharge from a tile drain working on a partially filled up pipe in no-pressure conditions should be calculated by an adapted equation based on the California pipe method, whereas the discharge from a completely filled up drain pipe working over pressure should be calculated as a ratio between 0.428 times the measured velocity and the pipe cross-section area

INFLUENCE OF THE CHANGE OF USING SOIL TO THE WATER QUALITY ON THE DRAINAGE SYSTEMS IN OBJECT LIDZBARK WARMIŃSKI

The study included groundwater outflow drainage systems and collected in the pond located at the agricultural use area in the portion of the drainage facility Lidzbark Warminski located on the Sępopolska Plain. The study was performed in two periods: the first one was in 1998–2000 (just after was made drainage), in which the discussed area was used as pasture, and the second in 2008–2010, in which after plowed of the soil was cultivated winter wheat. The aim of the study was to determine changes in water quality after the change of the way of land use. Examinations showed that as a result of the change of the way of using the area and ceasing of mineral fertilizing in waters of the pond was a reduction in the concentrations of the most mineral components, but an increase of pH reaction and concentrations of potassium, magnesium of sulfates and bicarbonates. In groundwaters observed increased the content of concentrations of mineral forms of nitrogen, phosphatic phosphorus, potassium, magnesium, general iron and bicarbonates, and a reduction in the concentrations of calcium, sodium, sulfates and chlorides. However in the water which outflow from drainage pipelines system from the research area was an increase of concentrations most of the determined substances, apart from ammonia nitrogen and chlorides

Quantitative, Qualitative and Thermal Aspects of Rainwater Retention on Wetland Roofs

Wetland roofs (WRs) are a multi-functional green infrastructure measure to mitigate the negative effects of climate change. The present work advances knowledge in the field of WRs by analyzing the performance of rainwater management, focused on water sufficiency, water quality and cooling potential. Automatic monitoring, covering weather conditions, temperature and the conductivity of WR water, and the amount of outflow into retention tanks, was supported with automated sampling of water for laboratory analysis of BOD5, phosphate phosphorus, suspended solids, electrical conductivity (EC), redox potential (Eh), color and pH. From April to September 2022, a precipitation deficit of 395.45 mm and a negative climatic water balance of 267.91 mm were observed. It was necessary to fill up the system several times in order to maintain water at the assumed level. In most cases, the values of EC observed during the monitoring period were higher than those reported for rainwater. Continuous monitoring of EC in the wetland was a useful tool for the observation of operating activities in the system; however, it was not sufficient for system control. BOD5 values did not exceed 6 mg dm−3 and were lower than reported for urban rainwater retention reservoirs. Suspended solids values did not exceed 27 mg dm−3. Color varied between 0 and 101 PtCo, with the highest values noted in July and the beginning of August. The pH value ranged between 7.28 and 8.24. The Eh varied between 155 and 306 mV, with lower values associated with the filling up of the wetland. Peak values of PO4-P were observed between the end of July and the beginning of September 2022, with a maximum concentration of 232 µg dm−3 utilized by the wetland within one month. Monitoring of the water and air temperature showed a thermal buffering effect of the wetland. The results of the research, conducted during the growing season, allow for better management of rainwater on the roof. However, there is a need to expand the scope of the analyzed water quality parameters. Although there are several limitations to the analysis, the present study partially fills the existing knowledge gap and may generate further interest in this topic among researchers and decision-makers