Agnes Classon

Seasonal salinity variations and hydrological conditions of the Gialova Lagoon

Tid och plats: kl 13.00-14.00 i Ahlmannsalen
Handledare: Stefano Manzoni
Examinator: Steve Lyon
Masterprogram i hydrologi, hydrogeologi och vattenresurser, 120 hp
Examensarbete i naturgeografi och kvartärgeologi, 45 hp
Abstract

Gitte Laallam

Transport and retention of heavy metals in contaminated soil and groundwater – A case study from Pukeberg Glassworks in Småland, Sweden

Tid och plats: kl 14.00-15.00 i Ahlmannsalen
Handledare: Jerker Jarsjö
Examinator: Stefano Manzoni
Masterprogram i hydrologi, hydrogeologi och vattenresurser, 120 hp
Examensarbete i naturgeografi och kvartärgeologi, 30 hp
Abstract

kl 15.00-15.15 - Paus

 

Ellinor Hallström

Payment for ecosystem services PES) and water resources management of the tropical mountain ecosystem páramo – A case study in the northern parts of Ecuador

Tid och plats: 15.15-16.15 i Ahlmannsalen
Handledare: Steve Lyon
Examinator: Stefano Manzoni
Masterprogram i hydrologi, hydrogeologi och vattenresurser, 120 hp
Examensarbete i naturgeografi och kvartärgeologi, 45 hp
Abstract

Mohammadreza Alavimoghaddam

Assessing the ability of the HEC-HMS rainfall-runoff model to simulate streamflow across Sweden

Tid och plats: 16.15-17.15 i Ahlmannsalen
Handledare: Steve Lyon
Examinator: Jerker Jarsjö
Masterprogram i hydrologi, hydrogeologi och vattenresurser, 120 hp
Examensarbete i naturgeografi och kvartärgeologi, 45 hp
Abstract

 

Abstract

Agnes Classon

Seasonal salinity variations and hydrological conditions of the Gialova Lagoon

Coastal lagoons are ecosystems being under constant natural, but also anthropogenic stress. Wind, tides, precipitation and evaporation, and salt-water inputs from the sea influence the lagoon system and cause very dynamic environments. Human activities such as agricultural production, fishing, swimming and hunting put additional pressure on these ecosystems, which, despite a very changing climate are highly productive and valuable for birds and animals, but also for the global fish and aquaculture industry. Especially important for fishing are the coastal lagoons in the Mediterranean, one of the most densely populated areas in the world and with an immense tourist industry. The human impact on the coastal lagoons in the Mediterranean is large, and eutrophication, over-fishing, and littering from tourists are very common issues resulting in a degradation of the water quality, and threatening of animal and plants species. Management plants are therefore highly needed, and to develop them, long-term monitoring to understand the hydrological settings are of importance. That was the main idea for this study, and Gialova lagoon, in the south-western Greece was chosen. Seasonal salinity changes, water temperatures, water levels and water flow direction were analyzed by installing electrical conductivity sensors. Evaporation and the lagoon water budget were calculated by installing climatic sensors. Also, the correlation between water levels, precipitation, evaporation and water temperature on salinity was analyzed. Water temperatures varied between 10°C in January to 30°C in July and salinity varied between 4 g L-1 to 40 g L-1. Evaporation rates were very large in summer but low in the winter, and the opposite occurred for the rainfall. Water levels were the highest in December after several months of high rainfall. When evaporation rates were high in the summer, water losses were compensated for by large inputs of sea water, and when precipitation was high in the winter, the lagoon gained a lot of water from fresh-water channels in the north. Evaporation and temperatures had the strongest influence on salinity. During climate change, with less winter rain and higher temperatures in the summer, salinity could increase due to more inputs of sea water and less inputs of fresh-water. This could be a threat to the lagoon ecosystem and a management plan could assist in maintaining a good water quality and to preserve rare birds, animals and plant species.

Gitte Laallam

Transport and retention of heavy metals in contaminated soil and groundwater – A case study from Pukeberg Glassworks in Småland, Sweden

As much as 80 000 sites, including landfills from glass production industries, are estimated to be contaminated in Sweden. One of these landfills is located near the glassworks factory of Pukeberg, in the municipality of Nybro, Southeast Sweden. It has been found to be severely contaminated with heavy metals, which have toxic effects to humans and biota. The aim of this study is to investigate hydrologic properties at Pukeberg, including groundwater velocities and their potential (spatial) heterogeneity that would affect the transport of metals. Metal concentrations in soil, pore water and groundwater were measured to investigate such metal transport and retention at the site. Slug tests were conducted at the site to determine local discharges and water velocities. For comparison, total groundwater flows through the landfill were estimated by considering water balances of the upstream catchment. Results showed a much higher groundwater flow through the landfill at Pukeberg when estimated from water balance constraints of the upstream catchment, compared to when up-scaled from local measurements of hydraulic conductivities and gradients within the landfill. This points to the existence of aquifer heterogeneity, including preferential flow paths and low-flow zones. Depending on flow path, transport velocities of heavy metals could therefore differ considerably. With a pH of 7 in pore water, and relatively low DOC (dissolved organic carbon) concentrations, environmental conditions were found likely to favour a strong retention for most of the metals investigated. This conclusion is supported by our estimates of Kd (the soil-water partitioning coefficient), derived from the in-situ ratio between soil concentrations and pore water concentrations at the landfill. These estimates were consistently higher than previously reported laboratory results from leaching tests, as well as guideline values from the Swedish EPA. For instance, Kd for Pb and As was found to be 50600 l/kg and 16400 l/kg, respectively. Thus, for most metals, a limited transport downstream could be expected. Indications of high aquifer heterogeneity within the limited area investigated in this study however give rise to uncertainties, for instance regarding the representativeness of the taken samples. Possible future analyses of extended sampling schemes could decrease these uncertainties.

Ellinor Hallström

Payment for ecosystem services PES) and water resources management of the tropical mountain ecosystem páramo – A case study in the northern parts of Ecuador

Latin America has pioneered the concept of Payment for Ecosystem Services (PES) as a strategy to improve the management of ecosystem services. Ecuador is not an exception, where many PES schemes have been implemented to protect the tropical mountain ecosystem “páramo” and the water resources these areas are generating for downstream societies. A successful PES scheme needs to achieve both targeted bio-physical objectives and at the same time benefit local conditions while not risking to sacrifice the local demand for ecosystem services. This balance is explored here in a case study focusing on the Río Grande watershed in the highlands in the northern parts of Ecuador by exemplifying community participation in the public PES scheme Socio Bosque (PSB) starting in 2009. The bio-physical conditions in the watershed are evaluated from a water balance approach. The local perceptions of the PSB and its impacts on local and regional ecosystem services were also characterized. The results showed that the annual discharge in the Río Grande watershed has decreased significantly from 1967-2015 and that the annual discharge was significantly lower between 1997-2015 compared to 1979-1997. Since precipitation did not decrease significantly during this period, the changes of the annual discharge are more likely depended on factors controlling the seasonal distribution of discharge and evapotranspiration in the watershed. For example, large scale land use changes coupled with a significantly warmer climate in the region could be a possible driver. Of course, this would not exclude other important factors such as changes in water demand and the supply of freshwater from the Río Grande watershed to downstream societies. The results of this case study showed that it is likely too early to see any improvements in the water balance components as a direct response to the implemented PSB scheme. Clearly, this motivates a need for continued evaluation of the local perception and monitoring of biophysical conditions to ensure that the need and demand for ecosystem services in a long-term perspective are maintained.

Mohammadreza Alavimoghaddam

Assessing the ability of the HEC-HMS rainfall-runoff model to simulate streamflow across Sweden

Computer modeling is the powerful tool for simulating nature’s behavior; however, still more efforts are need for reaching perfect simulation with computer models (especially in the hydrological field of study). In this Master’s thesis, the accuracy of the HEC-HMS computer model for long term rainfall-runoff simulation was evaluated across Sweden. Five different catchments from north to south of Sweden were selected and then simulation have done for 34 years of available data. Simulation was conducted using dail, monthly and yearly time scale resolutions. Results from the north to the south of Sweden were completely different. Simulated runoff and observed runoff in northern catchments followed the same pattern over different time scales but in the southern part of Sweden the results had different patterns in space and time. The best results with HEC-HMS were found in the northern catchments with steep main river slopes. In the southern catchments the model could not predict runoff in any realistic manner at any time and space scale. In total the HEC-HMS model cannot simulate the rainfall runoff for long periods of simulation across Sweden. This is especially true in southern parts of the country dominate with low elevation catchments; however, with regards to its ability for event-based simulation HEC-HMS could be a suitable tool to simulate flood event discharges that are needed for road or other hydraulic structures designs. But, this would require significant amounts of calibration and model development.