Experimental tests of thermal properties pertaining to vertical plant systems in the climate of Lower Silesia

Current fast development of cities causes obsolescence of green areas, which is partly the reason for the rise in temperature within cities, and for the creation of the “urban heat island” effect. In order to limit the heating of the agglomeration, alternative ways of introducing greenery to urban areas should be explored. One of these is the use of green walls on the façades of buildings. The vertical garden affects the air temperature, reducing the temperature on the surface of the heated building; furthermore, green walls improve the aesthetic values of the city, introducing peace into the harsh landscape of modern architecture, and they clean the air of toxins. In the present work, we discuss the problems pertaining to green wall thermals. Tests were run on experimental models during 2016 in Lower Silesia Province at the Agro-Hydrometeorology Observatory Wrocław-Swojec of Wrocław University of Environmental and Life Sciences. The main objective of those tests was to check impact of green walls on the environment and on the temperatures inside green wall. Observations were run on the south elevation on building. Performed tests indicated that plant cover works as isolation on wall. Due to these properties, it is possible to stabilize conditions on the wall behind the green panel. All the measurements were run simultaneously on the green wall, and on the reference model – a wall without plant cover. Comparing both models indicated that the green wall limits heating of the outer part of building, which can hold down variation of temperature inside the building

Hydrological Performance and Runoff Water Quality of Experimental Green Roofs

Within the scope of the conducted experiment the authors analysed the efficiency of runoff reduction by the system of extensive type green roofs. The observations were based on storm events in the area of Lower Silesia at the Agro and Hydrometeorology Station Wrocław-Swojec. The authors analysed the thickness of plant substrate, and also estimated the quality of runoff waters under the conditions of periodic atmospheric deposition. Also considered were such indicators as electrolytic conductivity, N, NO3−, NO2−, NH4+, P, PO43−. The experiment included roof substrates designed in two variants, with known hydraulic and physical properties of the soil material. The analysis was performed for models with vegetation layer based on pumice and zelolite, covered with five plant species from the sedum family. The modelling of the hydraulic properties was conducted with variably saturated medium, using the Hydrus 1D software. The performance of systems with primary layer thickness of 11 cm and 9, 8, 7, 6 and 5 cm was estimated. The designed models reduced the average peak flows to 89%, and in addition they caused a delay in the initiation of the runoff which was dependent on the intensity and distribution of rainfalls in time, and on the initial moisture of the profiles. Simulations, performed for variable substrate thickness, permit the conclusion that in the case of thin-layer profiles (5 cm), the relative retention index was decidedly lower and amounted to 35.9% for the substrate with zeolite (originally 60.6%) and 41% for the substrate with pumice (originally 65.7%). In the case of total nitrogen and phosphates, statistical analysis revealed significant differences (p < 0.05) in relation to specific concentrations in the rainwater and in the control surface. The total nitrogen in the runoff from the green roof was nearly twice as high as that in the rainwater and amounted to, on average, 8.3 mg L−1

Dynamics of Volumetric Moisture in Sand Caused by Injection Irrigation—Physical Model

The study was aimed at the determination of the dynamics of spatial distribution of moisture front, caused by pointwise application of water under conditions of high pressure. This was effected through a series of simulations of water injection to a porous material with particle size distribution corresponding to that of sand. The study was composed of six independent experimental series in which the sand monolith was supplied with water doses of 250, 500, 750, 1000, 1250, and 1500 cm3 under pressure (4 bar). At the same time, measurements of volumetric moisture were conducted with the use of TDR sensors, which were positioned within the soil in a regular grid pattern. It was demonstrated that the primary cause of water movement at the moment of injection is the pressure potential gradient of water molecules. The spatial reach of moisture change in relation to the injected water dose was also defined. It was also observed that in the course of water injection there is a risk of disturbing the structure of the porous material. The correctness of the adopted method was verified through the calculation of the water balance

CONDITION OF VEGETATION ON THE GREEN WALL WITH THE USE OF REMOTE SENSING METHODS

Research on the possibility of using remote sensing methods to evaluate condition of vegetation on the green walls were performed on experimental models in 2010–2011. Two models that differ from one another with vegetation layer were analyzed: a retention model (MR I) with substrate soil and an economic model (ME II) with hydroponic felt. In the individual panels plants representing shrubs, perennials and grasses were planted. In total, on experimental models 60 plant species was applied depending on the exhibition of the walls. The evaluation of the plants condition was performed based on field observations and the analysis of Normalized Difference Vegetation Index (NDVI). Evaluation of vegetation condition using remote sensing methods leads to the conclusion that the vegetation on retention model (MR I) have a much higher NDVI index value compared with the economic model (ME II). The comparison of the percent coverage of panels on retention model (MR I) and economic model (ME II) by the plants was done by separating the background plane from the plant surface. As a division criterion NDVI ratio in the range from -1 to 0.2 was taken. The results showed a clear contrast between the level of plant coverage of the examined models for individual facades. On the retention model (MR I) panels plant covering was significantly higher than on an economic model (ME II) where plant growth was limited. The growth of vegetation on the retention model (MR I) using substrate soil in plant panels was normal suggesting the potential use of such solutions in the climatic conditions of Lower Silesia. Vegetation on the economic model (ME II) is characterized by a worse growth throughout the growing season, which is why it is not recommended. The study showed that it is possible to evaluate the conditions of vegetation on the green walls with the use of remote sensing methods based on a modified photographic camera

EVALUATION OF PERFORMANCE OF SELECTED GREEN WALL SYSTEMS LOCATED IN THE LOWLANDS OF THE LOWER SILESIA

The study was performed in Wroclaw in growing seasons of year 2011 and 2012 on two models of modular green walls of various construction. Experimental models of green walls was made in the form of wooden houses with dimensions of 1,5×1,5×2,5 m and plant panels. Each elevation had 9 panels (33×33 cm) and the surface of a single wall was 1 m2. For the greening the walls was used 60 plant species representing shrubs, perennials and grasses (Ajuga reptans, Carex ornithopoda ‘Variegata ‘, Euonymus fortunei ‘Emerald’n Gold’, Festuca ovina ‘Glauca’, Sedum spurium, Spirea japonica ‘Japaness Dwarf’ and others). The study compares retention model (I) of green wall made with soil substrate having a thickness of 15 cm with an economic model (II), wherein the plant panels consisted of a layer of mineral wool and felt with thickness of 5 cm. Studies have shown that the economic model (II) did not work in the climatic conditions prevailing in the lowlands of Lower Silesia. It had an insufficient absorption capacity. Water outflow at the dose used for drip irrigation of 4,6 mm per 1 m2 came monthly to 50–77%, the covering wall of vegetation was approximately 60%, and the survival rate after the winter period reached only 5%. Retention model (I) was characterized by a much better absorbent properties. There was no water outflows , which indicates that the entire dose of irrigation was stored in the soil substrate. Plant development was normal, survival rate and their coverage in the analyzed period occurred up to 90%. On retention model (I) the best developed species was Sedum sp., Heuchera sp., Potentilla sp., Festuca sp. and Pachysandra sp.. On economic model (II) throughout the whole experimental period remained only plant of the genus Sedum sp., which indicating that these species can be used in systems of modular green wall under the climatic conditions prevailing in the lowland of Lower Silesia

ESTIMTION OF SOIL WATER RETENTION OF URBAN GREEN AREAS UNDER CONDITIONS OF PRECIPITATION DEFICIT ON THE EXAMPLE OF THE SZCZYTNICKI PARK IN WROCŁAW

The paper presents a characterisation of water relations and an estimation of the variability pertaining to soil water retention resources in the selected area of the Szczytnicki Park in Wrocław. The estimation was performed on the basis of the measurements of soil moisture performed in the years 2015 and 2016, and the results of monitoring and research conducted in an earlier period. The detailed study was conducted on a fragment of the park with the surface area of about 8.6 ha, situated north of the Japanese Garden, between the Mickiewicza and Kopernika streets. Soil moisture measurements were conducted with the TDR method, at 27 points, within the soil layers of 0-25 cm and 25-50 cm. On the basis of the analysis of spatial distribution of soil moisture it was observed that considerable and long-lasting moisture deficits of the active layer of the soil have occurred during the period under study. Moisture levels below the permanent wilting point (PWP, pF = 4.2) were noted on approximately 36% of the study area, in the layer of 25-50 cm. The reservoir with an area of 1.1 ha, situated centrally in the study area, did not cause any improvement of soil-ground water retention during the period of the study. That was due to the periodic lack of supply of the water system of the park from the intake of Oder river in which the water level decreased as a result of a drought

ESTIMTION OF SOIL WATER RETENTION OF URBAN GREEN AREAS UNDER THE CONDITIONS OF PRECIPITATION DEFICIT ON THE EXAMPLE OF THE SZCZYTNICKI PARK IN WROCŁAW

The paper presents a characterisation of water relations and an estimation of the variability pertaining to soil water retention resources in the selected area of the Szczytnicki Park in Wrocław. The estimation was performed on the basis of the measurements of soil moisture performed in the years 2015 and 2016, and the results of monitoring and research conducted in an earlier period. The detailed study was conducted on a fragment of the park with the surface area of about 8.6 ha, situated north of the Japanese Garden, between the Mickiewicza and Kopernika streets. Soil moisture measurements were conducted with the TDR method, at 27 points, within the soil layers of 0-25 cm and 25-50 cm. On the basis of the analysis of spatial distribution of soil moisture it was observed that considerable and long-lasting moisture deficits of the active layer of the soil have occurred during the period under study. Moisture levels below the permanent wilting point (PWP, pF = 4.2) were noted on approximately 36% of the study area, in the layer of 25-50 cm. The reservoir with an area of 1.1 ha, situated centrally in the study area, did not cause any improvement of soil-ground water retention during the period of the study. That was due to the periodic lack of supply of the water system of the park from the intake of Oder river in which the water level decreased as a result of a drought

ASSESSMENT OF CHANGEABILITY OF SOIL RETENTION RESOURCES IN THE SOUTHERN PARK IN WROCŁAW

The paper presents the characteristics of water relations and assessment of changeability of soil retention resources in the Southern Park in Wrocław. The assessment was done on the basis of measurements of soil water content in 2012 and 2013 also the results of field investigations from earlier years were taken into account. The measurements of soil water content were done using TDR method in the upper soil layers 0–25 cm and 25–50 cm in several dozen points (about 60) on the area of Park. It allowed to generate the maps of spatial distribution of soil water content. It was found that on the area of park there was observable diversity of retention resources accumulated in soils. Explicitly higher values of moisture were observed in the vicinity of park pond. The researches and analyses showed that excessive water content in analyzed soils in the area of Park occurred usually in spring and after torrential rains. The value and distribution of precipitation had the highest influence on soil retention resources forming

ASSESSMENT OF CHANGEABILITY OF SOIL RETENTION RESOURCES IN THE SOUTHERN PARK IN WROCŁAW

The paper presents the characteristics of water relations and assessment of changeability of soil retention resources in the Southern Park in Wrocław. The assessment was done on the basis of measurements of soil water content in 2012 and 2013 also the results of field investigations from earlier years were taken into account. The measurements of soil water content were done using TDR method in the upper soil layers 0–25 cm and 25–50 cm in several dozen points (about 60) on the area of Park. It allowed to generate the maps of spatial distribution of soil water content. It was found that on the area of park there was observable diversity of retention resources accumulated in soils. Explicitly higher values of moisture were observed in the vicinity of park pond. The researches and analyses showed that excessive water content in analyzed soils in the area of Park occurred usually in spring and after torrential rains. The value and distribution of precipitation had the highest influence on soil retention resources forming

EVALUATION OF THE IMPACT OF LAND USE CHANGES ON THE OUTFLOW FORMATION FROM LOCAL MICROCATCHMENT OF THE WUELS ARBORETUM AREA IN PAWŁOWICE

In the paper the impact of land use changes localised in catchment of the Wrocław University of Environmental and Life Sciences (WUELS) arboretum in Pawłowice near Wrocław on outflow from local micro-catchment was analysed. The study results show necessity for solutions that allow increasing the efficiency of rainwater management discharged from the sealed surfaces in the arboretum area. In this study the selected investments that are planning to improve water condition of forest habitat and to decrease flood risk of lower localised area were characterised. The planned investments include the development of various forms of small scale retention taking into account the aspect of improving water quality