The aim of this thesis was to estimate and possibly quantify ocean flow by utilizing conventional and novel observational methods as well as model results. Motionally induced voltages, from a cable-based observational system in the Baltic Sea, were analysed to determine their utility for ocean monitoring. The data set was examined as regards the influence of single- and multi-layer flow. Correlation analyses undertaken in the first study showed that the geoelectric installation is capable of providing good estimates of the net flow across the Visby-Västervik transect. The second study focused on possible effects of multi-layer flow on the signal. Comparisons were made with tidal-gauge geostrophic flow estimates, and a good agreement was found, except for a few brief winter periods characterized by significant discrepancies. The velocity fields from a three-dimensional model showed that these events coincided with strong surface and bottom currents, and hence the attenuated voltage signal was suggested as being caused by the non-uniform velocity distribution. The third study dealt with the deep-water flow through the Understen-Märket trench. Observational data indicated that this flow could be described by applying hydraulic theory. Since the passage is narrow compared to the internal Rossby radius of deformation, rotational effects could be neglected to lowest order. The theoretical predictions proved to agree well with the observational results. The final study examined the effects of the heat flux and the wind forcing on the circulation in Bahía de Concepción, Chile, where three field surveys were undertaken during the extended austral summer 2002. Hydrographic and current measurements were compared to local tidal-gauge records. Rough estimates of the barotropic and the baroclinic flow across the transect indicated an unusual vortex circulation during periods of weak wind forcing and strong surface heating; results which were corroborated by numerical simulations.

In this thesis a number of issues related to oceanographic problems have been dealt with on the basis of applying asymptotic methods.  The first study focused on the tidal generation of internal waves, a process which is quantifed by the conversion rates. These have traditionally been calculated by using the WKB approximation. However, the systematic imprecision of this theory for the lowest modes as well as turbulence at the seabed level affect the results. To handle these anomalies we introduced another asymptotic technique, homogenization theory, which led to signifcant improvements, especially for the lowest modes.  The second study dealt with the dynamical aspects of a nonlinear oscillator which can be interpreted as a variant of the classical two-box models used in oceanography. The system is constituted by two connected vessels containing a fluid characterised by a nonlinear equation of state and a large volume differences between the vessels is prescribed. It is recognised that the system, when performing relaxation oscillations, exhibits almost-discontinuous jumps between the two branches of the slow manifold of the problem. The lowest-order analysis yielded reasonable correspondence with the numerical results.  The third study is an extension of the lowest-order approximation of the relaxation oscillations undertaken in the previous paper. A Mandelstam condition is imposed on the system by assuming that the total heat content of the system is conserved during the discontinuous jumps.  In the fourth study an asymptotic analysis is carried out to examine the oscillatory behaviour of the thermal oscillator. It is found that the analytically determined corrections to the zeroth-order analysis yield overall satisfying results even for comparatively large values of the vessel-volume ratio. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

Water quality is an important issue in the whole world. Many countries suffer from periodic drought therefore water conservation is a major concern in these countries. By changing the natural water flow, the living conditions for many people changes. Irrigation is one of many ways to try to control the water sources and resources. One example of an irrigation project is located in Merawi in northern Ethiopia. In 2011, a 7030 hectare basin, with irrigation channels, was built. This gave the people there yearround water for their agricultural needs. There is a relationship between irrigation and groundwater levels. Irrigation causes the groundwater table to rise and that in turn makes the groundwater more exposed to chemicals from the surface. This can be a problem when groundwater is used for drinking water. In March 2013 a field study was conducted to investigate the chemical composition of the irrigation water and the drinking water in this area. Only a limited number of water samples could be taken, but field work and lab results in combination with literature have shown strong evidence that the surface water is mixing with the groundwater and may therefore affect the groundwater quality

I samband med att snön i Uppsala stad smälter får Fyrisån, som rinner genom staden, ett tillskott av salter och föroreningar. En av källorna till dessa salter och föroreningar är smältvatten från vägar. Flera stora vägar i Uppsala saltas för att minska halkrisken. Detta salt hamnar till slut i Fyrisån. I arbetet har det undersökts hur vattenkemin i Fyrisån ändras under vintern och våren samt om det sker någon förändring i vattenkemin när vattnet rinner genom Uppsala. Projektet har innefattat egen provtagning av åvatten och snö samt granskning av tidigare vattenkemidata från ån. Det som har konstaterats är att det i samband med vårfloden sker en utspädning av joner i vattnet. Efter vårfloden ökar jonkoncentrationerna igen. Det har även fastställts att det sker en ökning av salter i vattnet när det rinner genom Uppsala stad. På samma sätt har alkaliniteten minskat ju längre nedströms man kommer. Den största ökningen av jonkoncentrationerna var precis nedströms Uppsalas reningsverk. Resultat från detta arbete ger information om hur situationen ser ut i Fyrisån, var de största jontillskotten sker samt hur kemin ändras under vintern och våren.

Sveriges geologiska undersökning, SGU, och Naturvårdsverket, NV, tillämpar sig av olika geokemiska extraktionsmetoder för att analysera jordprover. Detta görs för att undersöka metallhalter i mark. SGU använder en metod som liknar den som rekommenderas av NV, men utan lakning i tryckkärl, och det är oklart om metoderna lakar samma jordfraktion och kan jämföras. Syftet med arbetet är att fastställa om SGUs och NVs extraktionsmetoder för jordprover är jämförbara. Detta har gjorts genom en kvalitets- och regressionsanalys, samt genom en statistisk analys. Proverna kommer från tre olika områden i Sverige och de är analyserade med både fin- och grovfraktion. För att hitta relationer mellan metoderna har SGUs och NVs analysresultat kopplats till NVs riktvärden för förorenad mark. Detta gjordes för att undersöka hur pass jämförbara SGUs resultat är med NVs riktvärden. Det visade sig att SGUs och NVs extraktionsmetoder för jordprover korrelerar väl med varandra och att de har en god förklaringsgrad. Prov som analyserades efter NVs metod extraherade mer metall än SGUs metod. Dessutom lakades högre metallhalter ur prov av finare fraktion än prov av grövre fraktion. Sammanfattningsvis är alltså SGUs och NVs extraktionsmetoder jämförbara.

The Baltic Sea is the one of the most studied seas area in the world and it is severely affected by human activities where eutrophication is the overall environmental problem. Although there is an international agreement that nutrient input to the Baltic should be reduced, the measures taken so far have not resulted in major reductions in nutrient inputs nor in environmental improvements. Sewage reduction is the most important factor for transparency improvement of the Baltic Proper and wetland restoration and change of N spreading time have no effective role in this aspect. Within the Baltic area, establishment of sewage treatment technology in Russia and Poland is more cost-effective than it would be in Sweden. Without this measure transparency improvement would be expensive. In Sweden NOx reduction is most cost-effective measure for transparency improvement in the Baltic Proper and without this measure the total cost would be ~ 58.5 million euro.

Rivers have been playing most important role as fresh water source and medium of nutrient transportation from terrestrial to aquatic ecosystem. Inorganic form of nutrients (DSi, DIN and DIP) are plant available mostly control the productivity of aquatic ecosystem. Transfer of these nutrients in higher concentrations cause harmful eutrophication in receiving water body. Study of dissolved inorganic nutrients concentrations in 12 Swedish rivers of different basin characteristics demonstrated both similar and varying behaviour from river to river and from season to season depending on catchment hydrology; land use and geology. Highest concentration did not coincide with the highest runoff. High DSi concentration observed in the unperturbed rivers however, high DIN and DIP concentration observed in agriculture dominated river followed by river basin dominated by industrial and urban activities. DSi and DIN concentration observed high in winter and decreased through spring to reach lowest in summer. DIP concentration although found low in summer but high concentration observed in early spring and early autumn. Rivers with low average runoff positively correlated with DSi and DIN concentration however, DIP demonstrated weak correlation.

Kraven på att företag skall arbeta med att minska sin miljöpåverkan har blivit hårdare från samhällets sida. Ett verktyg för småföretag som vill jobba systematiskt med miljöfrågor är miljödiplom, där Stockholms stads miljödiplom är ett av dessa. Stockholms stads miljödiplom är uppbyggt i tre nivåer och det tar ett år att genomföra varje nivå. Syftet med denna studie är att studera vilka konsekvenser och förändringar som sker när företag diplomerar sig med Stockholms stads miljödiplom. Detta kommer att analyseras utifrån organisationsteori med tonvikt på förändringar. För att svara på syftet har diplomeringsansvariga för sex företag, fördelade på två per nivå i miljödiplomet, intervjuats om sitt arbete med miljödiplomeringen samt hur miljöarbetet påverkat den dagliga verksamheten inom företaget. Resultat och slutsatser visade att kundkrav var den främsta faktorn till varför företagen diplomerade sig med miljödiplomet. Företagen valde Stockholms stads miljödiplom då det är bättre anpassat för småföretag än ISO 14001. Miljödiplomet uppfattas dock inte som tillräckligt känt i företagskretsar, utan där framstår ISO 14001 som mest erkänt. Trots miljödiplomet har inte miljöarbetet blivit direkt integrerat i företagens verksamheter vilket kan bero på bristande kommunikation mellan de diplomeringsansvariga och övriga anställda. De anställda var inte delaktiga i diplomeringsarbetet vilket kan vara en orsak till att inga större förändringar i den dagliga verksamheten hade skett i majoriteten av företagen. Företagen i studien har behövt mycket hjälp från Miljöcentrum, som är ansvariga för Stockholms stads miljödiplom, vilket innebär att kompetensen om miljödiplomet inte alltid skapades eller fanns inom företaget.

Water is a basic necessity for sustaining life and development of society. Proper management, protection and exploitation of water resources are the challenges imposed by population growth, increasing pressure on the water and land resources by competing usage. A good amount of clean water exists on Earth although it is normally inadequate in supply because of anthropogenic activities such as deforestation and land use change. Like many other catchments that provide economic activities for the community’s livelihood, the Chalimbana river catchment in Zambia has been deforested heavily and most of the local communities believe that deforestation could be the main contributing factor to the drying up of Chalimbana River. The objective of this study was to analyse the impact of deforestation on the stream flow of Chalimbana River Catchment with the help of a conceptual hydrological model, HBV. There was a 24% reduction in the annual average rainfall amounts for the deforested period as compared to the period before deforestation. The Qrec/Qsim ratios had revealed that the annual stream flow generation for the period after deforestation (1987 to 1996) for the Chalimbana River had decreased by about 12% as compared to the period with enough forest cover (1975 to 1985). The ratio of annual Qrec/P had indicated that after a 30% forest loss in Chalimbana catchment, there was a 33% increase in the generation of the stream flow. Based on the results that were obtained, a number of recommendations aiming at improving the catchment management were made.

This paper deals with relationship between irrigation and agriculture and conflicts within an irrigation system and as well between other stakeholders concerning the water. Irrigated lands are up to 2.5 times more productive compared to rain-fed agriculture. They are important element in the agriculture sector in Sub-Saharan Africa, and have been favoured by governments and donor agencies for their high rate of return. Without proper technical equipments or support negative impacts on the environment are linked to irrigation activities. Furthermore, a case study was made in Tanzania, Kiru Valley, regarding the tension between big scale and small-scale farmers as result from the water decline. The results demonstrate that the institutions do not have the power to solve the conflict. It is difficult to define the different stakeholders and the boundaries of the area that affect the amount of water in the valley.