In order to study the influence on blue-green algal nitrogenase activity of environmental variables in deepwater rice-fields (DWR), a laboratory study was planned on a DWR isolate of Calothrix (D764). The variables chosen were light, oxygen, combined nitrogen, phosphorus and iron. As availability of P is likely to play an especially important role for growth and nitrogen fixation in DWR, studies on phosphatase activity of the isolate were also included. The method used for measuring nitrogenase activity was acetylene reduction assay (ARA). In order to convert nitrogenase activity to nitrogen fixation, the conversion ratio of N(_2) : C(_2)H(_2) reduced was determined by comparing the total amount of N fixed with total C(_2)H(_2) reduced. The ratio was 1 : 4.1 and 1 : 5.2 at 85 and 10 µmol photon m(^-2) s(^-1), respectively. Changes in nitrogenase activity in batch culture were studied in relation to growth characteristics. Maximum activity (10.5 nmol C(_2)H(_4) mg d. wt(^-1) min(^-1)) was observed after two days of growth. During this period, juvenile trichomes (hence maximum heterocyst frequency) were abundant and cyanophycin granules were absent; chl a, phycobiliprotein and algal N decreased. It is suggested that the juvenile filament is the most active nitrogen-fixer during the growth of the alga. The response of nitrogenase to changes in light flux (down- or upshift) was rapid. The alga showed a marked drop in nitrogenase activity in the dark, but subsequent changes were slow, with detectable activity after 24 h. Higher nitrogenase activity was observed when the dark grown alga was re-illuminated, than the maximum activity found under continuous illumination. Nitrogen fixation and heterocyst differentiation were suppressed when 10 mg 1(^-1) NH(_4)-N was added to a batch culture. Fe-deficient cultures had lower nitrogenase activity and N content than Fe-sufficient cultures. Fe- deficiency led to the development of a series of new heterocysts apical to the basal ones. Addition of Fe to Fe-deficient cultures led to a marked increase in nitrogenase activity and loss of the degenerated basal heterocysts. The alga was capable of using a number of organic P substrates as the sole source of phosphorus and showed both cell-bound phosphomono- and phosphodiesterase activities. In batch culture, phosphatase activity was detected when cellular P content dropped to 0.98%. A brief study on the influence of the environmental factors on cell-bound phosphatase activities of the alga has been included. A brief comparison in nitrogenase activity of a UK field Rivularia population and bacterised laboratory isolate Rivularia D403 was made and probable behaviour of algae in DWR is discussed.

<p>Mosquitoes are found in extremely large numbers in the lower parts of the River Dalälven. In the year 2000 the mosquito nuisance was especially high, resulting in foundation of the Biological mosquito control project. Since 2001 mosquito larvae are controlled by using a biological pesticide BTI (Bacillus thuringiensis ssp israelensis). The mosquito fauna in the area is dominated by flood water mosquitoes, a group of mosquitoes that are very aggressive and form new generations of mosquitoes during every single flooding event during the summer. To be able to efficiently control the mosquitoes it is essential to know the extension and locality of the flooding. A flooding event is evaluated by how high the water level will reach and at which time the top of the hydrograph is accruing. There is a need for a tool for short time prediction of flooding events in the Nedre Dalälven region. In this study a hydraulic model in the software HEC-RAS has been used, here called HEC-RAS NEDA. The hydraulic model came up with good results when predicting water surface levels. The validation process made from figures of a period with large amplitude in water levels showed that the modelled water level was within ± 0,05 m from the observed water stands. It is a stable model that can handle 100-year flows with quick changes in the flow. The correspondence is good concerning the water levels and it functions well when studying the top of the hydrograph. HEC-RAS NEDA is an accurate and easy to manage tool for prediction of flooding in the lake of Bysjön, Österviken and Färnebofjärden. Modelled results have been compared with the model made by Swedish meteorological and hydrological institute on the request of Räddningsverket. The results from the two models shows large discrepancies, probably because of low accuracy data entered into the model from Räddningsverket. Räddningsverket has used the Geographical Sweden Data height data bank´and I used the height data from a laser scanned digital terrain model. Area studies have also been made according to how the area of the water surface changes with the water stand. These studies show that during the flood in year 2000, 55 km2 was flooded based on laserscanning in Färnebofjärden.</p> / <p>Mygg förekommer i extremt stora antal i området kring nedre delen av Dalälven. År 2000 var myggplågan särskilt stor vilket medförde att projekt Biologisk Myggkontroll bildades. Myggbekämpning har bedrivits i Nedre Dalälven sedan 2001 med ett biologiskt bekämpningsmedel, Bacillus thuringiensis ssp israelensis (BTI). Områdets myggfauna domineras av så kallade översvämningsmygg, en grupp stickmyggor som är mycket aggressiva och bildar nya generationer efter varje enskild översvämning under sommaren. För en effektiv bekämpning av mygglarverna krävs att man vet översvämningens omfattning och lokalisering. En översvämning bedöms med avseende på hur högt vattenståndet når samt vid vilken tidpunkt hydrografens toppvärde inträffar. Det finns ett behov av ett verktyg som kan utföra korttidsprognoser av översvämningar i Nedre Dalälven. I denna studie har en hydraulisk modell i programvaran HEC-RAS använts, här kallad för HEC-RAS NEDA. Den hydrauliska modellen fungerar bra till att användas för prediktering av vattenstånd i Nedre Dalälven. Valideringen av modellen mot värden under en testperiod med stor amplitud i vattenståndet visade att modellerade vattenstånd var inom ± 0,05 m från de uppmätta värdena. Modellen är stabil och klarar av att hantera 100-årsflöden med snabba flödesfluktuationer. HEC-RAS NEDA är ett noggrant och lätthanterligt predikteringsverktyg för översvämningar i Bysjön, Österviken och Färnebofjärden. Överensstämmelsen är god gällande nivån av vattenståndet och den fungerar bra för att studera hydrografens topp temporärt. Modellerade resultat har jämförts med karteringar som Sveriges meteorologiska och hydrologiska institut har gjort på Räddningsverkets begäran. Resultaten skiljer sig betydligt mellan HEC-RAS NEDA och Räddningsverkets modell, troligen på grund av att Räddningsverket har stora svagheter i indata till modellen. Räddningsverket har använt Geografiska Sverige Data-Höjddata och modellen HEC-RAS NEDA är framtagen med höjddata från en digital terrängmodell baserad på laserscanning. Areella studier i GIS över hur arean av vattenspegeln förändras med vattenståndet visar att Färnebofjärden under augusti år 2000 lade 55 km2 under vatten.</p>

Catastrophic events such as dam failures or severe floods are considered to be of low probability, although their consequences can be extremely high and might include loss of life. Earlier studies have linked circumstances surrounding historical darn failure events to actual loss of life and produced formulations using statistical analysis of these events. Shortcomings of these methods include the inability to adjust life-loss estimates based on the type of darn failure, global averaging of population at risk, and ignoring the dynamics of the evacuation process. The main objective of this research is to develop a practical and improved life-loss estimation approach for use in dam safety risk assessment and emergency planning. The methodology is specifically formulated to overcome the limitations of previous. purely empirical, approaches. The approach takes into account the spatial and temporal distribution of flood water depth and velocity, fate of buildings, simulation of warning diffusion, and tracking the movement of people from their original location towards safe shelters. The model created, called LlFESim, is designed to serve multiple function s. First, it can be used in a Deterministic Mode using best estimate inputs to obtain point estimates, or to test different policies for evacuation as well as different times of the day and for different dam breach flooding scenarios. Second, the Uncertainty Mode represents input and parameter uncertainties to provide estimates of life loss, and other variables relating to warning and evacuation effectiveness, as probability distributions. These distributions of life loss can be combined with estimates of the uncertainties in other risk assessment inputs, to obtain estimates of uncertainties in risk assessment results, including evaluations against tolerable risk guidelines. Two communities were used to demonstrate the model performance. Deterministic Mode results display the various possible model outputs. Sensitivity analysis for the Deterministic Mode shows that the effect of warning issuance time is the dominant factor in the estimated life loss. However, other factors play an important role such as the time of day, effectiveness of the warning system, and shelter location. Uncertainty Mode results demonstrate the effect of uncertainties in model parameters and inputs on the model results.

The topic of my thesis is: {\clqq}Measure for protection of inhabitans in case of occurrence of a special flood on the selected water work of the 3rd category``. A special flood is flood caused by a defect or accident (rupture of the dam of the water work increasing the water level or accumulating water) or by emergency solution of a critical situation on the water work causing the occurrence of an extraordinary event (crisis situation) on the territory underneath the water work. For the elaboration of my thesis I selected the {\clqq}sludge bed in Hodějovice`` water work, the owner and operator of which is the Heating Plan České Budějovice a.s. (shar. Comp.). In case of occurence of a special flood, the local parts of České Budějovice, Mladé and Nové Hodějovice would be endangered. To prevent the unnecessary damage to health or even loss of life, the plan of protection for the territory underneath the water work from a special flood had to be elaborated. My task was to evaluate the sufficiency of this documentation and to supplement passibly the necessary data by the local examination and anylysis of the documents and the suggest additional protective measures.

Mosquitoes are found in extremely large numbers in the lower parts of the River Dalälven. In the year 2000 the mosquito nuisance was especially high, resulting in foundation of the Biological mosquito control project. Since 2001 mosquito larvae are controlled by using a biological pesticide BTI (Bacillus thuringiensis ssp israelensis). The mosquito fauna in the area is dominated by flood water mosquitoes, a group of mosquitoes that are very aggressive and form new generations of mosquitoes during every single flooding event during the summer. To be able to efficiently control the mosquitoes it is essential to know the extension and locality of the flooding. A flooding event is evaluated by how high the water level will reach and at which time the top of the hydrograph is accruing. There is a need for a tool for short time prediction of flooding events in the Nedre Dalälven region. In this study a hydraulic model in the software HEC-RAS has been used, here called HEC-RAS NEDA. The hydraulic model came up with good results when predicting water surface levels. The validation process made from figures of a period with large amplitude in water levels showed that the modelled water level was within ± 0,05 m from the observed water stands. It is a stable model that can handle 100-year flows with quick changes in the flow. The correspondence is good concerning the water levels and it functions well when studying the top of the hydrograph. HEC-RAS NEDA is an accurate and easy to manage tool for prediction of flooding in the lake of Bysjön, Österviken and Färnebofjärden. Modelled results have been compared with the model made by Swedish meteorological and hydrological institute on the request of Räddningsverket. The results from the two models shows large discrepancies, probably because of low accuracy data entered into the model from Räddningsverket. Räddningsverket has used the Geographical Sweden Data height data bank´and I used the height data from a laser scanned digital terrain model. Area studies have also been made according to how the area of the water surface changes with the water stand. These studies show that during the flood in year 2000, 55 km2 was flooded based on laserscanning in Färnebofjärden. / Mygg förekommer i extremt stora antal i området kring nedre delen av Dalälven. År 2000 var myggplågan särskilt stor vilket medförde att projekt Biologisk Myggkontroll bildades. Myggbekämpning har bedrivits i Nedre Dalälven sedan 2001 med ett biologiskt bekämpningsmedel, Bacillus thuringiensis ssp israelensis (BTI). Områdets myggfauna domineras av så kallade översvämningsmygg, en grupp stickmyggor som är mycket aggressiva och bildar nya generationer efter varje enskild översvämning under sommaren. För en effektiv bekämpning av mygglarverna krävs att man vet översvämningens omfattning och lokalisering. En översvämning bedöms med avseende på hur högt vattenståndet når samt vid vilken tidpunkt hydrografens toppvärde inträffar. Det finns ett behov av ett verktyg som kan utföra korttidsprognoser av översvämningar i Nedre Dalälven. I denna studie har en hydraulisk modell i programvaran HEC-RAS använts, här kallad för HEC-RAS NEDA. Den hydrauliska modellen fungerar bra till att användas för prediktering av vattenstånd i Nedre Dalälven. Valideringen av modellen mot värden under en testperiod med stor amplitud i vattenståndet visade att modellerade vattenstånd var inom ± 0,05 m från de uppmätta värdena. Modellen är stabil och klarar av att hantera 100-årsflöden med snabba flödesfluktuationer. HEC-RAS NEDA är ett noggrant och lätthanterligt predikteringsverktyg för översvämningar i Bysjön, Österviken och Färnebofjärden. Överensstämmelsen är god gällande nivån av vattenståndet och den fungerar bra för att studera hydrografens topp temporärt. Modellerade resultat har jämförts med karteringar som Sveriges meteorologiska och hydrologiska institut har gjort på Räddningsverkets begäran. Resultaten skiljer sig betydligt mellan HEC-RAS NEDA och Räddningsverkets modell, troligen på grund av att Räddningsverket har stora svagheter i indata till modellen. Räddningsverket har använt Geografiska Sverige Data-Höjddata och modellen HEC-RAS NEDA är framtagen med höjddata från en digital terrängmodell baserad på laserscanning. Areella studier i GIS över hur arean av vattenspegeln förändras med vattenståndet visar att Färnebofjärden under augusti år 2000 lade 55 km2 under vatten.

This work presents hardware and software design for River wireless monitor Rabbit Core module RCM5400W. It describes possible solutions for measurement of river characteristics, in particular water level height. Pressure method measuring and selection of important electric parts are described in more detail. The software for Rabbit Core module RCM5400W and also web sites are described here.

Many multipurpose reservoirs are situated in the low mountain range of Germany. Most of them are necessary for drinking water supply and flood protection as well. Other utilizations are recreation, water power and the downstream low water regulation during dry seasons. The operation rules of the reser-voirs have to be optimized to meet the different requirements of use. One tool within this framework is a management system for river basins including all reservoirs and their specific operation rules affecting the downstream reaches. As an optimization objective for instance the minimization of inundation risks can be defined. In this case the risk can be defined as hydraulic and hydrologic safety of the reservoir itself and the risk due to inundation and damaging in the downstream regions. Considering the European Water Framework Directive the ecological aspect of reservoir management is one more point in the optimization process. To es-tablish a pilot project the software TALSIM will be applied to river catchments in the ore mountains (Saxony).

The Diploma thesis deals with the safety assesment of the small water reservoir Bartošovice III during the floods, according to requirments of TNV 75 2935 (technical standard). First two chapters are devoted to the description of the dam purpose. Following chapter deals with the summary of basic information and documentation, including hydraulic analysis. In the following section maximum permissible safe water level is determined together with the maximum check flood water level in reservoir which reflects the flood wave transformation. In the final evaluation the comparison of the maximum permissible safe water level with maximum check flood level is carried out. At the end of the thesis recommendations leading to ensuring of reliability and safety of water reservoir are listed.