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72 Uppsatser om Pelting rain - Sida 5 av 5
Intensivt regn i Sverige 2009-2011 : En kartläggning över händelser av intensivt regn och dess konsekvenser
Sammanfattning Klimat- och sårbarhetsutredningen (SOU 2007:60) spår en framtid då Sveriges klimat till större del präglas av intensivt regn, och diskuterar konsekvenserna detta kommer innebära. Så väntas framtiden bli, men hur ser det ut idag? Syftet med uppsatsen är att kartlägga den samtida förekomsten av intensivt regn i Sverige och dess konsekvenser, i syfte att skapa en referenspunkt till diskussionerna om framtidens regnintensiva klimat och hur det kommer påverka samhället.Materialet studien bygger på har inhämtats från flera håll, men främst kommer det från SMHI, tidningsartiklar, räddningstjänster och kommuner. Sedan har en sammanställning gjorts där de identifierade händelserna analyserats kvantitativt och rumsligt. Studien är avgränsad till att endast inkludera händelser under sommarmånaderna juni, juli och augusti eftersom flest händelser av intensivt regn bedöms inträffa då.Resultatet visar stor geografisk spridning av inträffade regn, och liten kronologisk spridning.
Sammanvägda avrinningskoefficienter i rationella metoden : en jämförelse mellan idag och 1970-talet
Storm water is rain and melted snow that runs off, primarily from impervious surfaces.Future storm water management is facing the challenges of increased precipitation, asclimate changes, and increased areas of impervious surfaces due to the expansion anddensification of the cities. Impervious surfaces reduce the potential for water to infiltratein the ground leading to increased surface runoff and higher peak discharge.The runoff coefficient is closely related to the percentage of impervious surfaces andrepresents the maximum percentage of a catchment that can contribute to runoff. In thisstudy, the objective was to evaluate the weighted runoff coefficient for three differenturban types; apartment buildings, townhouses and residential areas and a comparisonbetween today and the 1970`s was made.The runoff coefficient was determined by manual mapping of the different surface typesin each area based on data in the form of orthophotos and aerial photographs. The surfacetypes that were mapped were asphalt, permeable areas, tiles, sand/gravel and roof.Tiles and sand/gravel were the most difficult surface types to map. In order to see towhat extent these categories influenced the weighted runoff coefficient a sensitivityanalysis was carried out and the runoff coefficient based on surface type was changed indifferent scenarios.The results of the sensitivity analysis showed that the surface types tiles and sand/gravelhad little impact on the weighted runoff coefficient which in mainly due to the fact thatthe percentage of these surfaces types of the total area is small.The result of the study showed that the largest change in the runoff coefficient occurredin residential areas where the increase in the percentage of impervious surfaces causedby new roofs in the form of porches and garages and from paved or tiled driveways.
Fröodling av Raj- och rörsvingel i Sverige
Festulolium (Festulolium) and tall fescue (Festuca arundinacea) has not been grown inSweden over a longer period. So far there is no greater area cultivated, but the area isincreasing. Festulolium and tall fescue are expected to eventually replace meadowfescue in many leyseed mixtures to dairy cows in southern and central Sweden. Tallfescue has in recent years become popular again. Festulolium is a hybrid betweenryegrass and fescue.
Dagvattendammars reningseffekt : påverkande faktorer och metodik för statistisk modellering
Storm water is defined as runoff from precipitation such as rain or snow. It is collected in sewage disposal systems and since it mainly originates from urban areas it can contain high levels of heavy metals, nutrients and oil etc. Polluted storm water is currently treated by different methods such as wet ponds, constructed wetlands and filter strips. This study investigates these methods, which in earlier studies have shown to give varying results regarding their treatment efficiency.This thesis has been written on commission of SWECO VIAK and was aimed at studying those parameters that may affect the treatment efficiency of nutrients and heavy metals in storm water treatment facilities (STF:s). Through literature studies the dominating treatment processes in ponds and wetlands were examined.
Impact of Eucalyptus plantations on pasture land on soil properties and carbon sequestration in Brazil
Soil organic carbon (SOC) stocks and fluxes in forest ecosystems are influenced by natural and human disturbances. In the tropical regions the highest impacts on disturbance in forest C cycles are related to human activities such as conversion of natural lands to cropland and pasture areas and to forest plantations. The disturbances in the forest C cycles will release CO2 emissions to the atmosphere triggering global warming. In this study the focus was set in subtropical soils in Brazil, south extreme region of Bahia. The aim of the study was to investigate whether reforestation of Eucalyptus plantations under former pasture areas will help mitigate climate change through carbon sequestration.
Nursing technique and growth environment of Rabbit fish (Siganus guttatus) in the area of Tam Giang lagoon, Thua Thien Hue
SummaryIn the area to the east of Hue city, in Vietnam, lays Tam Giang lagoon, one of Asia's largest lagoons, with an area of 22,000 hectares. This lagoon is suitable for aquaculture. One reason for this is because the salinity differs from sweet to salty in different parts of the lagoon. The Vietnamese Government advocates an increase in environmentally-friendly aquaculture and the fish Siganus guttatus (Rabbit fish) is a candidate for this. This fish eats mainly algae and can be cultivated in a polyculture.
Utveckling och tillämpning av en GIS-baserad hydrologisk modell
A distributed hydrological rainfall-runoff model has been developed using a GIS integrated with a dynamic programming module (PCRaster). The model has been developed within the framework of the EU-project TWINBAS at IVL Swedish Environmental Research Institute, and is intended for use in WATSHMAN ? a tool for watershed management developed at IVL. The model simulates runoff from a catchment based on daily mean values of temperature and precipitation. The GIS input data consist of maps with soil type, land-use, lakes, rivers and a digital elevation model.
Allanblackia stuhlmannii ? a tree under current domestication: what are the soil requirements?
Allanblackia is a genus of trees that grows in the rainforests of West, Central and Eastern Africa. Its big fruits contain seeds very rich in oil which has been used by
local communities for cooking and making soaps. The native stands are threatened by overexploitation and the demand for the oil is much greater than the supply.
Domestication programs, aiming at introducing the trees to small holder agroforestry systems, have been started for some of the species. The main aim of this study was to investigate the soil requirements of Allanblackia
stuhlmannii in terms of chemical and physical parameters, as revealed by the soil conditions in native stands. Another aim was to see if these varied along an altitudinal transect.
Utnyttjandet av ligghallar hos dikor och kvigor av köttras under vintern :
Cattle used for meat production can be held outside all year round and due to the legislation they should have access to shelters or other buildings for protection against the elements giving them a dry and clean bedding. There are different opinions concerning their need of protection and the question about necessity of shelters for cattle is of current interest due to a less profitable economy in meat production and the investment costs for shelters. The aim of this study was to acquire more knowledge about the natural behaviour of cattle concerning their use of shelters. The basis of the study was a series of questions regarding when animals choose to stay in shelters, if shelters were used less when they had access to protecting vegetation, how temperature and weather conditions affected the use of shelters and the influence of distance between shelter and feed. Behavioural studies was conducted at five different farms where six groups of suckler cows and heifers of following breeds and crossbreeds were observed; Aberdeen Angus, Charolais, Hereford, Scottish Highland Cattle, Simmental and the Swedish breeds SKB and SRB.
Shelter use of horses during Swedish summer in relation to weather conditions and insect abundance
Outdoor housing of horses? best fulfils the horses? need for physical activity and it is an alternative to the more cost and energy demanding indoor housing in stables. Furthermore, if outdoor housed horses have access to shelter they can generally cope well with adverse
weather conditions such as high or low ambient temperature, heavy rain or strong winds.
In this study, the daytime shelter-seeking behaviour of three groups of horses housed outdoors was studied during the summer. The aim was to evaluate whether shelter use is related to weather variables (e.g., ambient temperature and wind speed) and insect harassment.
The shelter-seeking behaviour was studied for three different groups of horses: Group 1) eight individually housed horses in paddocks that had access to three different shelter types (C: closed on three sides with roof, R: open on three sides with roof, W: closed on three sides without roof), Group 2) 25 group housed mares with foals on pasture with access to shelters
C, and Group 3) ten mares without foals on pasture without access to shelter. Each group was studied for eight days.
Val av liggplats och väderskydd hos dikor vid utedrift vintertid
If you keep cattle in a herd outside all year round on big varying grounds, their possibilityto perform their natural behaviour increases. This way of keeping cattle requires that youprovide them with their other needs, like shelter and a dry and clean resting place.According to the animal welfare authority´s regulations on livestock farming, only animalsthat are suited to stay outside during the cold season are allowed to be kept outside. Theyshould also have access to a shelter or another building that gives them protection from theweather and wind and provides a dry and clean resting place.Research has shown that as long as cattle do not get exposed to precipitation and wind theywill manage low temperature well. Some of the things that will affect how well the animalshandle different climates are the isolation ability of the fur, the animals´ body size and thefeed intake. A dry lying place that is both insulating and moisture absorbent is also of greatimportance.
Dagvatten i Märsta : förslag till anläggning för ekologisk hantering samt metodöversikt
Stormwater in urban areas has been treated as a problem for a long
time. The large proportion of impermeable surfaces inhibits the water
from infiltrating in the ground to the same extent that it does in nature.
This causes intensive surface flow during rain, which in turn causes
inconveniences such as decreased accessability, floods and increased risk
of desease spreading. Drainage through pipes is the traditional and usually
functional metod for storm water disposal. That is as long as water flows
are moderate. But precipitation varies naturally in amount and intensity
and additional impermeable surfaces make some pipes insufficient for
heavy or lasting precipitation.