UNIVERSITY OF GOTHENBURG Department of Earth Sciences Geovetarcentrum/Earth Science Centre

Catchment-basin characterization

for a water-protection area

in Norra Vi, Ydre municipality

Amanda Hansson

ISSN 1400-3821 B901 Bachelor of Science thesis Göteborg 2015

Mailing address Address Telephone Telefax Geovetarcentrum Geovetarcentrum Geovetarcentrum 031-786 19 56 031-786 19 86 Göteborg University S 405 30 Göteborg Guldhedsgatan 5A S-405 30 Göteborg SWEDEN

Abstract Water is one of our most important natural resources, which is why it is essential to protect water bodies that are used or have the potential to be used as drinking water. According to the European Water Framework Directive (2000/60/EC, article 6) all wells that supply more than 10m3 water per day or serve more than 50 people should have an established water protection area accompanied by regulations and restrictions.

The water resource that supplies Norra Vis municipality with drinking water is located in a glaciofluvial deposit. The water body is in close proximity to lake Sommen, one of the larger lakes in Sweden. The well supplies both permanent and seasonal residents with drinking water and produces an average of 40m3 water per day. This water resource currently lacks a water protection area.

The objective of this thesis is to formulate a proposition for a water protection area in Norra Vi based on the catchment-basin characterization and understanding of both the natural and anthropogenic factors that potentially impact on this water resource. The proposed water protection area includes sensitive parts of the groundwater formation, and is divided into three zones, a primary, secondary and tertiary zone. These zones are defined after how long time it takes for the groundwater water to reach the well. Threats to the quality of this water resource are listed along with suggested prevention measures, such as limitations regarding land use and activities within the catchment basin. The results from this thesis are meant to be a part of the application for a new water protection area, in which the county makes the final decision.

As guidance for this thesis the handbook 2010:05 of the Swedish EPA has been used. The handbook gives general advices regarding procedures for establishment of water protection areas and these have later been adapted to the suit the prevailing conditions for the catchment basin. In accordance to the handbook data of water occurrence, value, vulnerability, consequence and risks for the water supply intake have been gathered and analysed.

Keywords Water, Grundvatten, Water protection area, Norra Vi, Ydre municipality

I Sammanfattning Vatten är en av våra viktigaste naturtillgångar, därför är det angeläget att skydda de vattentillgångar som används eller har möjlighet att användas som dricksvatten. Enligt EU:s ramdirektiv för vatten (2000/60/EG artikel 6 och 7) ska alla vattentäkter med ett uttag på minst 10 m3 vatten per dag eller tillhandahåller fler än 50 personer ha ett fastställt skyddsområde med tillhörande skyddsföreskrifter.

Vattentäkten som försörjer Norra Vis kommun med dricksvatten är belägen i en isälvsavlagring. Grundvattenmagasinet ligger i nära anslutning till sjön Sommen, en av de större sjöarna i Sverige. Brunnen försörjer både fast boende och säsongsboende med vatten, och i snitt pumpas 40m3 vatten per dag. Vattentäkten saknar i dagsläget ett skyddsområde.

Syftet med denna uppsatts är att utforma ett förslag på ett vattenskyddsområde för Norra Vi. Dräneringsområdet har blivit avgränsat både för yt- och grundvatten, och dess storlek och form utgör den preliminära avgränsningen för vattenskyddsområdet. Dräneringsområdet för grundvatten delades in i tre zoner, en primär, sekundär och tertiär zon. Zonerna är utformade efter vattnets rinntid, alltså tiden det tar för vattnet att nå brunnen. Aktiviteter och markanvändning vilka potentiellt kan skada vattenkvalitén är beskrivna i rapporten samt förslag på förebyggande åtgärder, så som begränsad markanvändning och vissa aktiviteter. Resultatet från rapporten kommer att användas som underlag då kommunen ansöker om nytt vattenskyddsområde. Ansökan kommer att lämnas in till länsstyrelsen, som fastställer skyddsområde och skyddsföreskrifter.

Information och råd om hur adekvata vattenskyddsområden framarbetas har huvudsakligen hämtats ur Naturvårdsverkets handbok om vattenskyddsområde 2010:05. Data om vattenförekomster, värde, sårbarhet, konsekvenser och risker för grundvattnet har utvärderats.

Nyckelord Vatten, Grundvatten, Vattenskyddsområde, Norra Vi, Ydre komun

Preface This report is the result of an investigation for a possible water protection area for a groundwater reservoir in Norra Vi, Ydre municipality. The project was carried out in collaboration with HIFAB AB in Kalmar.

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Table of content Abstract ...... I Keywords ...... I Sammanfattning ...... II Nyckelord ...... II Preface ...... II 1. Introduction ...... 1 1.1 Aim ...... 1 1.2 Background ...... 1 2. Description of study area ...... 3 2.1 Geography and climate ...... 3 2.2 Local geology and hydrogeology ...... 4 2.3 Groundwater use and supply ...... 7 2.4 Surface water ...... 7 2.5 Water quality ...... 8 2.6 Land use ...... 8 3. Risks ...... 8 3.1 Potential pollution from point sources ...... 9 3.1.1 Energy wells ...... 9 3.1.2 Local industries ...... 9 3.1.3 Graveyard ...... 10 3.1.4 Old landfills ...... 11 3.1.5 Traffic accidents ...... 11 3.1.6 Drains and sewers ...... 11 3.2 Potential contamination from diffuse sources ...... 11 3.2.1 Agriculture ...... 12 3.2.2 Foresting ...... 12 3.2.3 Cattle and livestock keeping ...... 13 3.2.4 Roads ...... 13 3.2.5 Climate change ...... 14 3.2.6 Boats in lake Sommen ...... 14 3.2.7 Oil tanks ...... 14 4. Method and material ...... 14 4.1 Local geology and hydrology ...... 15 4.2 Catchment basin ...... 15 4.2.1 Catchment basin for groundwater ...... 15 4.2.2 Catchment basin for surface water ...... 15 4.3 Zonation of area ...... 15 4.3.1 Zonation of groundwater catchment basin ...... 16 4.3.2 Zonation of surface water catchment basin ...... 16

4.4 Calculating smallest area required supporting the well of Norra Vi ...... 17 4.5 Value of the water resource ...... 18 4.6 Classification of hazards ...... 18 4.6.1 Criteria for classification ...... 18 4.6.2 Risk matrix for hazardous events ...... 20 5. Results ...... 20 5.1 Local geology and hydrology ...... 20 5.2. Catchment basins for groundwater ...... 23 5.3. Zonation for groundwater catchment basin ...... 24 5.4 Catchment basin for surface water ...... 25 5.5 Zonation for surface water catchment basin ...... 26 5.6 Calculating smallest area required to support the well of Norra Vi ...... 28 5.7 Value of water resource ...... 28 5.8 Classification of hazards ...... 29 5.8.1 Summary of hazardous events and vulnerable states ...... 29 5.8.2 Risk matrix for hazardous events ...... 31 6. Discussion ...... 32 6.1 Local geology and Hydrology ...... 32 6.1.1 Geological and Hydrological conditions of Norra Vi ...... 32 6.1.2 The relationship between the groundwater reservoir and lake Sommen ...... 32 6.1.3 The possible occurrence of a groundwater divider ...... 33 6.2 Catchment basins and zonation for groundwater ...... 34 6.3 Catchment basin and zonation for surface water ...... 35 6.4 Calculating the smallest area required to support the well of Norra Vi ...... 35 6.5 Value of water resource ...... 36 6.6 Threats facing the groundwater quality ...... 36 6.7 Potential prevention measures ...... 36 7. Conclusion ...... 38 8. Acknowledgement ...... 38 Bibliography ...... 38 Appendices ...... 0 Appendix 1 ...... 0 Appendix 2 ...... 1

1. Introduction

1.1 Aim The aim of this project is to formulate a proposition for a water protection area in Norra Vi (Figure 1). This is done to help Ydre municipality ensure a good water quality in a long-term perspective for the residents in Norra Vi. The water protection area should account for all forms of anthropogenic contaminations; both point and diffuse source. A contamination is here defined as a substance which has the potential to affect the quality of the water in such ways that it becomes unfit to use as drinking water (Naturvårdsverket, 2011). The area in which the groundwater reservoir is located will be divided in to different zones where suggestions for limitation of certain activities and forms of land uses that could potentially harm the water quality will be made. A risk assessment will be conducted where potential threats will be listed and classified after severity and likeliness of occurrence.

1.2 Background In a national perspective Sweden holds many natural water resources of good qualities. In areas where water resources are scarce or used by humans in larger scales there are great needs of protection (Naturvårdsverket, 2002). The Swedish governments environmental work aims to reduce the negative impacts humans have on the environment to achieve long-term sustainable levels. In reality this means that all present major environmental issues should be solved within the timeframe of one generation. With this as an aiming symbol the Swedish government has presented 15 different environmental goals, where goal number two states “Groundwater of good quality” (SGU, 2001). According to the European water framework directive (2000/60/EG) all public water treatment plants and/or water bodies that serves more than 50 people or supplies more than 10 m3 per day as an average are required to provide a good water quality. This directive compose the grounds for a EU-mutual set of regulations to protect surface, ground and coastal waters and is a step towards achieving the Swedish national environmental goal “Groundwater of good quality” (Naturvårdsverket, 2011). This is not a law but rather an environmental goal, which states that all larger public wells should have an established water protection area before 2015 (Länsstyrelsen Östergötland 2., u.d.).

The groundwater resource, which this report is focused on, is located in Norra Vi (figure 1). The coordinate for the well is in SWEREF99 TM: 6416047, 520858, and the well is located in close proximity to the shore of lake Sommen (marked dot in appendix 1). The well supports both permanent and seasonal residents with drinking water and produces an average of 40m3 of water per day. There are great seasonal variations in the water demand due to the in proportion large number of vacation homes connected to the well (Norra Vi Vattenverk, 2008). The water treatment plant only supports permanent and seasonal residents with drinking water, and is not connected to any industries or public buildings (Kommun, 20008).

In a water protection area there are limitations and restrictions concerning activities that may pose a threat to the water quality. These restrictions should prevent contamination in both long and short terms, and can for example restrict the usage of pesticides and other chemicals. If a lake is located within the water protection area it may also limit the usage of for example motorboats (Länsstyrelsen Östergötland 2., u.d.). Due to the slow turnover, polluted groundwater is extremely difficult to remediate. This is why it is essential to prevent contaminants from reaching the groundwater reservoir. According to the Swedish environmental protection agency (EPA) there are three steps to prevent contaminated water from being used as drinking water. The first step is a protective measurement to, within the water protection area, prevent activities that may potentially harm or contaminate the water.

1 If this is not done properly the second step is to discover contaminations and remediate the ground before the pollutant reaches the groundwater. Warning systems and barriers can be used to discover contaminations and to minimize the spread. A barrier can occur naturally, as for example a groundwater divider, less permeable soil or a lake that dilutes the contamination. If there is no natural barrier a technical one can be put in place. This can for example be a boom or a system to turn of the water intake to the drinking water system. The third stage is to make sure that if the pollutant reaches the groundwater it is diluted into acceptable levels or treated before reaching the households.

Figure 1. Pin needle shows the location of the well in Norra Vi, Sweden.

Declaring a water protection areas and announcing injunctions results in:

• That protection for the drinking water supply is improved • The importance of the water reservoir is clarified • The area of the reservoir is clarified by being specified into different physical plans • Environmental rules for activities in the area are put in place

According to EPA, to determine the size and shape of the water protection area, the catchment basin needs to be calculated. This is the area where surface water and precipitation most likely has a potential to reach the groundwater reservoir. The water protection area will be divided in to different zones according to the time it takes for the water to reach the point of discharge. This is dependant up on distance to the reservoir as well as the soil type. To establish the magnitude and form of protection

2 needed for the water supply a risk analysis will be preformed along with an evaluation of the water resource (Naturvårdsverket, 2011).

A suggestion for a water protection area can be handed in from the organization responsible for the water supply. As in this case, it is most common for the municipality to hand in the suggestion, but in rare cases a company or community association is responsible for the application of the water protection area. The application is sent to the county where the final decision regarding the water protection area is made (Länsstyrelsen Östergötland 2., u.d.).

2. Description of study area

2.1 Geography and climate Norra Vi is located in Ydre municipality, along the shore of the southernmost point of lake Sommen, at lat/long 57.882737,15.351334 (see Figure 1). This area belongs to the southern Swedish highland, an area that during times of de-glaciation formed an arctic archipelago. The landscape is characterised by fissures, forming low valleys and plateaus high over today’s coastline (Hillefors, 1979) (VISS, u.d.).

The climate in Norra Vi consists of four seasons, winter, spring, summer and fall, with temperatures dropping below zero in winter, and reaching above 20 in summer (see figure 2) (Norwegian Meteorological Institute, u.d.). The monthly precipitation varies between 33 and 72 mm per month (February and July). In general the winter and spring is the driest period of the year, and summer the wettest (see figure 3) (Mitt resväder, u.d.).

Figure 2. Graph shows average, average max and average min temperatures for Norra Vi.

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Figure 3. Average monthly precipitation in mm in Norra Vi.

2.2 Local geology and hydrogeology The southern Swedish highland where the water reserve is located includes parent rock areas above the highest coastline, which stretches from Skåne to southern parts of Närke. The region is characterised by crystalline bedrock and sediments resilient to weathering (VISS, u.d.). According to SGU geological maps the underlying bedrock here is of intrusive form, consisting of both felsic and younger porphyritic granite, as for example augen gneiss (Aneblom, Pousette, Müller, & Engqvist, 1997) (SGU, u.d.). Sommen is a graben lake which bays are located in shear zones in the parent rock. The community of Norra Vi is located in a shear zone at the end of the Norra Vi costal inlet (Ydre Kommun 1., 2002).

In 1986 the area around Sommen was classified as a natural area of national interest due to the great diversities of the landscape. In the area around the Norra Vi costal inlet large amounts of glacifluvial alluvium has been deposited. The community of Norra Vi is located on one of these glacifluvial deposits (Liman, 1986). The groundwater in these glacifluvial alluviums consists of open aquifers in sandy and gravelly layers with varying thickness. To these environments glacial lake sediments and shallow stream sediments are included. In the glacifluvial deposit of Norra Vi there is only one registered well used for drinking water (VISS, u.d.). The depth of the sedimentary deposit increases towards the lake from SE of the community (Ingenjörsbyrån VIAK, 1958). A map showing the different local soil classifications made by SGU can be seen in figure 4. Glacifluvial and gravelly glacifluvial sediments dominate the area closest to the lake, where the well is located. The thickness of the soil is very varying, and several areas have a thin or no soil coverage (SGU Kartgenerator, 2012).

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Figure 4. Soil map over Norra Vi from SGU

The well supporting Norra Vi with its local water supply is located in the quaternary deposit previously mentioned near lake Sommen (Aneblom, Pousette, Müller, & Engqvist, 1997). The water reservoir where the well is located has the identification number EU_CD SE641590-147369, which is an attribute given from the Swedish water authorities (VISS, u.d.) (Wingqvist, 2012). The largest source of groundwater in this area is located in the sandy/gravelly alluvial deposits close to the southern shore of Norra Vi’s coastal inlet in Lake Sommen. The groundwater-bearing layer, which the well is located in, is shown in figure 5 (VISS, u.d.). This area correlates with the sedimentary deposit seen in figure 4.

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Figure 5. The groundwater bearing layer from VISS , with the expected direction of flow for the groundwater.

From hydrological pumping the daily discharge of water, without major impacts on the water table, was estimated to bet at least 315m3/day. Several holes were drilled and the pumping was conducted at site 5 (see appendix 1), which is the site where the well is located today (Ingenjörsbyrån VIAK, 1958). According to SGU hydrogeological map the glacifluvial alluvium where Norra Vi is located has a potential discharge of 25-125l/s (SGU Kartgenerator, 2012). In 1990 the well produced water volumes of 19m3/day, but had a higher potential discharge (Aneblom, Pousette, Müller, & Engqvist, 1997).

The flow of water in the deeper sedimentary layers is distinctively higher than that in the overlying sandy/silty layers. The low permeability of the surface layers suggests that the main recharge area for the groundwater-bearing layer is located south of the well, where the surface sediment is coarser. It is also suggested, from the same investigation, conducted before the well was established, that the lake has limited influence of the groundwater flow (Ingenjörsbyrån VIAK, 1958).

In the report from VIAK several test holes were drilled, and the water levels were measured for a timer period of 1 ½ month. During this period pumping was performed for approximately one month near pipe number 5. The results from these measurements are seen in appendix 2, with the location of the different holes displayed in appendix 1. The graph in appendix 2 shows a temporary depression of the water level in all holes when the pumping commenced, but a quick recovery of the water levels. There is also a correlation with water levels in the drilled holes and precipitation. The precipitation during the same time frame is shown in appendix 2. Once pumping was completed the water table at pipe number 5, where the pump was located near, did not recover to the same levels as the other pipes.

6 2.3 Groundwater use and supply Norra Vi is a parish with approximately 235 permanent residents and 450-550 seasonal residents (Norra Vi, u.d.). The fact that there are more seasonal than permanent residents results in a highly seasonal demand of water, and the consumption of 40m3 per day is just an average. The usage is probably considerably higher during the summer months and much lower during winter.

The soil type here, glacifluvial alluvium, has according to SGU hydrological map a potential draft of 25-125l/s (see figure 6) (SGU Kartgenerator, 2012). Water infiltrated in the sedment south of the well is stored as groundwater and slowly moves towards lake Sommen (S-N direction). The groundwater- bearing sediment is dominated by glacifluvial sediment along with gravely glacifluvial sediment and till (see figure 4).

Figure 6. Shows potential draft from sedimentary deposits as well as location of landfills. Map from SGU. 2.4 Surface water Sommen has a total area of 132km2 (Länsstyrelsen Östergötland 1., u.d.), and together with its drainage area of 1910km2 (SMHI 2., u.d.) it stretches over several municipalities. The eastern parts of lake Sommen are extremely nutrition poor and have a visibility of 5-9m. The lake and its surrounding area are home to several sensitive species of fish and birds. The most interesting specie is the char, a fish that derives from the last ice age. In the bay of Norra Vi there are two natural areas of interest, since these are two of very few places where the char comes to play. The lake is a very popular recreation area and houses many leisure boats (Ydre Kommun 1., 2002). At the south-eastern part of the shore of Norra Vi, where the harbour for the leisure boats is located, there is a smaller stream

7 entering the lake. This stream runs from south to north, and is stretching a few hundred meters through forested areas.

2.5 Water quality The average annual mean temperature of the shallow groundwater at the study site varies between 6- 6.5°C (Aneblom, Pousette, Müller, & Engqvist, 1997). In a report from Vatteninformationssystem Sverige (VISS), published in 2009, several chemical substances were measured and analysed in surface waters. None of the measurements taken showed any anomalies and in conclusion no polluted areas could be found. Heavy metals have been measured in the whole county of Östergötland. Copper (Cu) anomalies where found to be low (Aneblom, Pousette, Müller, & Engqvist, 1997), and the concentration do not exceed the threshold values set by the Swedish national food administration (Livsmedelsverket 1., u.d.). The average uranium (U) concentration in the county is approximately 40% higher compared to the average in Sweden. In the local area around Norra Vi several rocks with increased concentrations of radon can be found. Radon can be transported with groundwater and therefore there is a potential for high concentrations of radon in groundwater from wells drilled in hard rock (Aneblom, Pousette, Müller, & Engqvist, 1997), and therefore elevated levels of radon should not pose a threat to the well of Norra Vi.

2.6 Land use Within the groundwater bearing layer (see figure 5) the land use goes as following (VISS, u.d.):

• Conurbation 0,8% • Farmland 5,6% • Grazing-land 3,3% • Forest 58% • Clear-cut areas 9,4% • Wetlands 7,1% • Water 15,8%

This shows that the local area for the groundwater bearing layer is sparsely developed and mainly consisting of forests or open areas such as farmlands or clear-cut areas.

3. Risks A risk assessment should always be conducted within the catchment basin of the water protection area. This is an evaluation of all potential and existing threats that could affect the quality of the drinking water (Naturvårdsverket, 2011).

The potential degree of contamination for a groundwater-shed is defined as the sum of the potential pollutants from different potential sources of contamination that can have an effect on the groundwater reservoir. To define what risk a certain unwanted event poses to the groundwater quality of the catchment basin, the probability of occurrence has to be taken in consideration. A high-risk event has a potential severe consequence combined with a high probability of occurrence. The potential contamination is defined as the potential degree of contamination multiplied with the vulnerability of the watershed.

The vulnerability of a watershed is defined as its resistance for pollutions. Main factors affecting the watershed are resistant are: grain size of the surface and subsurface materials, their structure and 8 organic content, depth to groundwater and biological conditions. Soil with high content of gravel has a high vulnerability compared to soil consisting mainly of clay particles (Vattenmyndigheten Norra Östersjöns vattendistrikt, 2007).

3.1 Potential pollution from point sources Following list states potential and existing point sources for contamination:

• Energy wells (pumps for geothermal heating and earth heat) • Local industries: o Visskvarns träsliperi (SVT 1., 2012) • Graveyard • Old landfills • Traffic accidents • Drains and sewers

3.1.1 Energy wells Geothermal shallow energy mainly consists of solar energy that is passively stored in the ground. The most common form of energy well is drilled in bedrock and has a depth of 100-300 meters (Geotec, 2012). Fluid circulates in a closed system of polythene-tubes, connecting the heat pump aggregate to the borehole. The polythene-tube usually goes all the way down to the bottom of the borehole. At some sites, for example where the ground is contaminated from industrial chemicals, a borehole could affect the groundwater quality in a negative way. If a borehole is taken out of service and if located in a water protection area it is highly recommended that it is refilled or sealed (SGU, 2008).

The most common fluid to be used in energy wells for smaller facilities in Sweden today is a mixture of water and 20-30% ethanol. The Swedish equivalent to the food and drug administration (Läkemedelsverket) requires that denaturant such as isopropanol or n-butanol is mixed with the ethanol to make it undrinkable. This can have environmental consequences if the substance is leaked at a contingently leakage since addition of these chemical prolongs the degradation process. It is mainly the denaturant that can affect the quality of the water adjacent to the heat pump. Even small leakages can affect both smell and taste of drinking water in the local surrounding, but normally they do not pose a threat since the fluids dilute and decompose (SGU, 2008).

According to the National environmental protection agency regulation 2003:16 boreholes are prohibited within primary protection zone and license is needed within the secondary zone (SGU, 2008).

3.1.2 Local industries The old industrial factory Visskvarns träsliperi is branch-classified as an old paper industry (location on figure 7). In general, areas where paper industries previously have been active are often likely to be contaminated. The branches of paper industries are therefore classified as 1 after the MIFO scale. The MIFO scale is the Swedish national classification system for polluted areas. The risks are divides in to four categories, where 1 is the greatest risk and 4 the lowest. The risks are classified after magnitude of consequence for humans and environment in the area. The classification goes as follows:

1. Very high risk 2. High risk 3. Moderate risk 4. Low risk 9 This system is mainly used for the county when prioritising polluted areas (Länsstyrelsen Västra Götalands Län, u.d.). Even though Visskvarns träsliperi has been classified as a paper industry it is not similar to the paper industries found today, and therefore this particular industry is classified as a moderate risk, class 3. The reason for this classification is that the factory has been closed for 80 years and no chemical use is recorded. Leachate water from fresh bark is poisonous for algae and fish and could therefore pose a possible threat. There is a slight possibility that the premises later on were used for storage of dangerous chemicals. This uncertainty makes the area harder to classify. What also has to be taken in to account is the long period that has passed since the factory was in use. It is likely that any potential leachate water has been diluted by this time. Due to the uncertainty for chemical storage and its close proximity to surface water of high protective value the industrial area is classified to pose a moderate risk (SVT 1., 2012).

Figure 7. Green arrow shows the location of Visskvarns träsliperi

3.1.3 Graveyard A church and a graveyard are located within the watershed with close proximity to the well (VISS, u.d.). Graveyards pose a potential risk for pollution due to the use of pesticides. Pesticides are mainly used to prevent weed from growing on gravel paths. Gravel is a very permeable material and infiltration here is high if a more impermeable layer is not found underneath (Vattenmyndigheten Norra Östersjöns vattendistrikt, 2007).

Ash that is spread at memorial places only has a minor impact on the chemical composition of the soil. Slight increased levels of silver, copper and ten are found as residuals from amalgam. There is also a marginal increase of heavy metals that can be traced to the increased accumulation of heavy metals in

10 bone marrow with longer lifespan. In summary the elements that seems to have the most impact on vegetation in these areas are increased levels of phosphor, silver and calcium. The elements spread by ash mainly affects the topsoil, but with time some of the heavy metals will start to move down in the ground (Svenska kyrkans församlingsförbund, 2009).

The same elements are released from degradation of bodies buried in the ground. If bodies are buried in an unsealed casket or without a casket organic material will be released during decomposition. High rainfall and shallow groundwater increases the risk for contamination of the groundwater. This can lead to high bacteria count, elevated chemical oxygen demand and formation of ammonia and nitrate (Fetter, 1999). It is therefore recommended to always bury coffins with at least one-meter margin from the groundwater (Svenska kyrkans församlingsförbund, 2009).

3.1.4 Old landfills Many landfills leak liquids, generally termed leachate, which can contaminate groundwater. The threat different landfills pose depends mainly on the geological material underneath. If the landfill is situated on a layer of clay the risk for contamination is generally low. The risk for contamination when a landfill is situated on for example gravel is considerably higher (Fetter, 1999).

The landfill in Norra Vi is located close to the shore on the eastern side of the coastal inlet of Sommen. It was in use between 1950-1972 and its main purpose of use was incineration of domestic waste (SVT 2., 2012). According to SGU geological maps the landfill is located on solid rock with a thin discontinuous layer of soil. Chemicals can leach from this site in to Sommen, where it will be diluted before reaching the shore of Norra Vi. Even so, the potential for leached contaminants to be transported in the groundwater to Sommen from this area is insignificant.

3.1.5 Traffic accidents Within the groundwater-bearing layer there are 7,4km public road (VISS, n.d.). The main road here consists of two lanes and has a width of 3.6-6.5m (Trafikverket 3. , u.d.). There potential impact a road can have on the local environment is classified from A-D, where A indicates a great impact on the local environment, and D a low risk for impact. The whole stretch of road within the groundwater reservoir is classified as D, meaning that there is a low risk for environmental impact due to the minor water infiltrated in the ground (Naturvårdsverket, 2011).

3.1.6 Drains and sewers Nutrition, mainly as phosphor, can leak from private sewages and contribute to over-fertilization of the ground. The main indicator for leakage from sewages is E. Coli. E. Colie is released from fresh feces and can lead to infections if found in drinking water (Smittskyddsinstitutet, u.d.). It is mainly old houses in rural areas and small urban communities that have inadequate sewage systems. Inventories of private sewage systems in Sweden showed that around 40% of all systems needed to be upgraded (Naturvårdsverket, 2008).

3.2 Potential contamination from diffuse sources Following places and activities can be a potential source of diffuse contamination in the area:

• Agriculture o Over-fertilization o Leakage of nitrogen and phosphor • Foresting o Felling

11 o Leaching of nutrients o Log dump • Cattle and livestock keeping o Contamination from animal waste • Roads o Combustion gasses and ware from roads and tires o Ice control salting • Climate change o Flooding • Boats in lake Sommen o Pollution from paint used on boats o Gas from boats o Emptying of latrine • Oil tanks

3.2.1 Agriculture

Fertilizers Nutrition is leaked from all agricultural land, but when fertilizers are added there becomes an excess of nutrients in the ground (Jordbruksverket, 2013). Most fertilizers contain phosphor, nitrogen and potassium. Phosphor has low mobility in soil and does therefore not pose a significant threat to the groundwater quality. The content of potassium is usually low and all though it is mobile it has not shown to cause any problems with groundwater. Nitrogen on the other hand is mobile and therefore poses the highest threat (Fetter, 1999). Plants cannot take up the entire excess nutrient and it will eventually percolate down in the ground, where the plants roots can no longer reach it (Jordbruksverket, 2013).

Pesticides Pesticides are chemicals applied to the crops to prevent and control weeds, insects and other pests, but can also used for defoliation, desiccation and growth control. Pesticides can have major impacts on the groundwater’s quality since solubility and mobility allows them to infiltrate in the soil and reach the groundwater. Most pesticides used today are biodegradable to some extent, but their metabolites can be found in the groundwater. The highest risk for contamination is found where different pesticides are mixed and where equipment is rinsed and re-filled. These areas usually show higher levels of contamination than where the crops are grown (Fetter, 1999).

Irrigation If irrigation is used more water is added to the field than what is needed for evapotranspiration. The excess water is infiltrated down in the soil to the groundwater table. When the water moves down in the ground it mobilize chemicals from pesticides and fertilizers. The salinity in the soil may increase since the evaporation of water leads to a concentration of natural salts found in the irrigation water (Fetter, 1999).

3.2.2 Foresting

Deforesting 58% of the area within the catchment basin of Norra Vi consists of forest (VISS, u.d.). If parts of this area are exposed to de-foresting, it might lead to a rise of the groundwater table and increased runoff. 12 An increased runoff can in turn lead to increased transportation of organic material to adjacent watercourses and lakes. The higher content of organic matter gives water a brownish color. Hummus is naturally acid and can lower the pH of the water to <6 (Löfgren & Lundin, Fakta skog - Mer humus i svenska vatten, 2003). Hummus can act as a nutriment for bacteria and fungus, and lead to high levels of microorganisms in the water system. If these levels are high in the drinking water it may make the water taste bad, and can also lead to issues with pathogenic organisms (Löfgren, Forsius, & Andersen, 2003). Machines used in connection with de-foresting poses a threat since they can leak petroleum during refueling or when in accidents.

Forest drainage The rise of the groundwater table associated with deforestation can be counteracted with ditching. Ditching lowers the groundwater table and acts as channels, removing excessive groundwater from the area. This is required for plantation of new forest in wet areas, since the pores in the topsoil has to contain a mixture of water and oxygen for new plants to strike root (Magnusson, 2009). Ditching is often performed after felling of big areas. A few months after ditching the dikes will be re-filled with sediment and plans, which leads to decreased efficiency. The dikes should then be reopened to enhance the oxygen supply to the roots of the trees in the soil. During ditching and reopening of dikes there is a risk for enhanced transportation of sludge to adjacent water bodies (Skogsstyrelsen, u.d.). If the groundwater table is lowered down to the mineral soil layer the leakage of hummus can decrease to levels lower than before ditching (Löfgren & Lundin, 2003).

Log dump There are both permanent and temporary log dumps. Temporary log dumps are common during deforestation, where timber is stockpiled adjacent to the deforestation site before transportation (Miljösamverkan, 2011). Leakage of nutrients and other substances is associated with rain- and snowfall on the log dump. The excess of nutrients can contaminate the groundwater if infiltrated. It is therefore important when storing trees for a long period of time to store them so that leaching substances will not reach the groundwater (SLU, n.d.).

3.2.3 Cattle and livestock keeping

Farm animal waste The waste from farm animals may pollute the soil and groundwater with viruses, bacteria, nitrogen and chloride. If animals are kept at an open field the waste will be dispersed over a great area, minimizing the risk for pollution. If animals on the contrary are kept in a small area the waste will be concentrated, increasing the risk for contamination. Barns, barnyards and feedlots are particularly at risk for concentration of animal waste. When rainwater infiltrates feces substances can mobilize and eventually leach into the groundwater. The waste may be used as fertilizers for crops. If used during winter on frozen fields it can have toxic effects on the ground and groundwater during spring melt (Fetter, 1999).

3.2.4 Roads The main forms of contamination from roads are exhaust emission, wear and tear from vehicles on the road and leakage of petroleum products. Ice controlling salt is the most common source of pollution that can have an impact on the groundwater (SGI, 2006).

Traffic quantity: In Norra Vi the only major road within the catchment basin for groundwater is national highway 561. The yearly average daily traffic on this road is approximately 255 vehicles (Trafikverket 1., u.d.).

13 There are great seasonal variations in this area, with a peak in august of more than 410 passing vehicles per day. The yearly average daily traffic with trucks is 12 passing trucks without cargo and 4 trucks with cargo (Trafikverket 2., u.d.).

Ice control salting The primary salt used to deice roads is rock salt, consisting of sodium chloride (Fetter, 1999). According to the Swedish transport administration 97 % of the road salt is made up from sodium chloride, the remaining 3 % is mainly gypsum and moisture. Very small quantities of sodium ferrocyanid are added to improve handling of the salt (Trafikverket, n.d.). The salt and additives are carried from the roadway in runoff and wash into surface streams or seep into groundwater (Fetter, 1999). The chloride anion does not break down and as a consequence it can be transported over long distances and accumulate around the well (SGI, 2006). When distances between roads and wells are greater than 100 meter, it is not usual that road salt affects the water in a way that it gets unfit to use as drinking water (Rosén, 2006).

3.2.5 Climate change Climate studies indicate that Sweden in the future can expect a milder and wetter climate (IPCC, 2001). This increases the risk for flooding and submersion, which can lead to the spreading of contaminants to ground and surface water.

3.2.6 Boats in lake Sommen In most private owned boats petrol 95 is used as fuel. In smaller boats it is common carry on an extra petrol can for refilling of the fuel tank (Svenska petroleum & biodrivmedelinstitutet, u.d.). These extra cans does usually hold up to 20 litres of petrol. If petrol is leaked near the shore there is a potential for the petrol to affect the groundwater quality.

3.2.7 Oil tanks In farms petroleum products and chemicals used for agriculture are often stored in tanks above ground. Leakage of these products can release chemicals, which can be infiltrated in the ground and taken up by the groundwater. This threat is significantly high if large quantities of chemicals are leaked within a close proximity to the well.

Some homeowners and farms store their tanks for heating oil and fuel under ground. Underground tanks can leak from both the tank itself and, more commonly, from the associated piping. Steel tanks are vulnerable for corrosion and fiberglass tanks lack the strength of steel and may crack (Fetter, 1999).

4. Method and material Information used in this report is mainly gathered from literature studies and analyses of existing data. The main source for these literature studies is a handbook from Naturvårdsverket (Swedish EPA), called Naturvårdsverkets handbok 2010:5 om vattenskyddsområde (2011). Sverige Geologiska Undersökning (SGU) is the main reference for studies regarding local geology and hydrology. Several maps are used to describe the prevailing geological and hydrological conditions. These maps have been downloaded from the website of SGU at the and are therefore hard to reference too (SGU Kartgenerator, 2012). The scale used for the hydrological map and geological map is 1:250 000, and for the soil map 1:100 000. If looking for futher studies of these maps the area of study is located within 520-540N/S, 6420-6400E/W for the hydrological and geological map, and 520-530N/S, 6420- 2610E/W for the soil map.

14 As mentioned in the project description it is the county who makes the leagal desissions wether the area should be classified as a water protection area or not. Since the county plays a crucial part in forming water protection areas a great source of information has been gathered from Östergötland county (Länsstyrelsen i Östergötland).

4.1 Local geology and hydrology The local geology and hydrology is further described in this section through cross sections. These cross sections area based on investigations conducted in 1958 from VIAK. A total of 10 holes were drilled and grain sizes were analysed.

4.2 Catchment basin A catchment basin is an area where precipitation will, either by runoff or infiltration, have the highest potential of reaching a specific water source. A catchment basin has been created both for the groundwater-bearing layer and for the surface water. The close proximity from the well to the lake makes it necessary to establish a catchment basin for the surface water, since this water does most likely have an impact on the groundwater.

4.2.1 Catchment basin for groundwater The catchment basin was created from using height curves, drill hole data and topographical features. Since no drilling has been performed to determine a water divider the catchment basin has been designed after some assumptions. The first assumption is that water does not easily flow from south to north. One of the strongest arguments for the presence of a water divide is the fact that no easily permeable material can be found going south from the well (drill hole 3, figure 10 and 11). The till here can be found on almost the same altitude above sea level as Sommen. The likeliness for a groundwater flow to pass through the material in drill hole 3 in a south to north direction can be seen as less likely, and therefore this is one of the assumptions taken in to consideration when creating the catchment basin. The waters more natural direction of flow would be to the west, where the till is found at lower heights (figure 11). Another assumption is that the water south of the catchment basin flows down to the stream instead of flowing north in the less permeable material (see figure 12). These are only assumptions and to confirm these theories more data would be required in the form of test drilling.

4.2.2 Catchment basin for surface water The catchment basin for the surface water was taken from SMHI Vattenwebb (sub basin 40555) (SMHI 2., u.d.). Due to the wells close proximity to lake Sommen, the whole lake and its catchment basin was included.

4.3 Zonation of area Different areas within the catchment basin have different needs of protection. When dividing the catchment basin in to different zones the need for protection is the main factor. The need for protection is mainly determined by the waters rate of transportation. If a contamination occurs in an area with a short transportation time to the well this is more critical compared to if the contamination would occur in an area with a closer proximity but with longer transportation time. This is due to the fact that it gives less time to react and stop the contamination from reaching the well. With a long transportation time there will be more time to react and take the right actions. The area of the catchment basin is divided in to different zones depending on how long it takes for the water from a point to reach the well, according to the method formulated by the Swedish EPA (Naturvårdsverket. 2011). In the different zones different restrictions and limitations will prevail to prevent any sort of pollution to

15 reach the well. The zones will be divided differently for ground and surface water after its different needs. The area around the well will be divided in to three different zones, the primary zone (inner zone), secondary zone (middle zone) and the tertiary zone (outer zone). The primary zone is the zone closest to the well and will therefore have the strongest restrictions (Naturvårdsverket, 2011). The surface water will be divided in to two zones – a primary and a secondary zone. The secondary zone will consist of the whole catchment basin excluding the primary zone. Due to the very large size of the surface water catchment basin the primary zone is the only one were restrictions potentially will be implemented.

4.3.1 Zonation of groundwater catchment basin When forming zonation for the groundwater catchment basin the transportation rate for the groundwater and sensitive infiltration areas are of essence. It is therefore very possible for the different zones not to be connected with each other, in contrast to the surface zonation. In general the boundary between the primary and secondary zone is drawn where the groundwater resident time exceeds 100 days. The limit between the secondary and tertiary zone is where the time it takes for the water to reach the well exceeds 1 year. To estimate the average rate of transportation a radial flow of water will be assumed. In the used method the active volume of the groundwater will be calculated from using the draft of water during a specific period of time. This will then result in a nominal residential time for the groundwater. This calculation does not take any consideration to recharge or the hydraulic gradient (Naturvårdsverket, 2011).

( ! # $ = &' )*+

Where: Q = average draft in m3/ day t= transportation time in days r= distance from the well in m b= depth of the groundwater bearing layer in meters ne= the groundwater bearing layers kinematic porosity

The most conservative numbers from this calculation was then used to create the different zones. Due to the small size of the catchment basin for groundwater the area outside of the primary and secondary zone will be the tertiary zone, and no calculations will be made for this area.

4.3.2 Zonation of surface water catchment basin For surface water the primary zone includes the area in which a contamination can reach the shore of the lake within 12 hours (Naturvårdsverket, 2011). The time it takes for a contamination in the surface water to reach the shore where the well is located is mainly dependent on the force and direction of the wind. There are four factors affecting this transport time:

• The amount of water transported to the lake in relationship to the lakes shape and depth • Prevailing wind-conditions • Stratification • Ice

The rate of transportation in lakes is around 3% of the wind speed for contaminations on the surface in ice-free conditions. A contamination that mixes with the water moves at a rate of approximately 1.5% of the prevailing wind speed (Nerheim & Jacobsson, 2011). When calculating the transport time the most threatening scenario should be dealt with, which in this case would be contamination that does

16 not mix with the water but rather stays on the surface (Naturvårdsverket, 2011). Since the part of the lake that is included in the catchment basin is very elongated in a N-NW/S-SE direction, the wind direction that will have the most influence on the transport time will be winds blowing from N-NW. The well is located in the southern part of the lake and therefore the quickest transportation time will be achieved if winds are blowing N-NW. In degrees the most disadvantaged wind direction will be somewhere between 300-330°. To get the greatest speed of transportation the highest wind speed measured within a 10-year period should be used (Naturvårdsverket, 2011). Since winds in other directions than 300-330° will have little possibilities to transport the contamination to the shore where the well is located, the highest wind speed measured in this direction was chosen.

The closest wind station in this area is located in Horn, approximately 30km away. According to wind- data from SMHI the highest wind speed measured during the last 10 years between 300-330° was 9m/s. If the rate of transportation is approximately 3% of the wind speed, it means that the maximum speed of transportation in the lake would be 0.27m/s. The bay of the lake, which is included in the catchment basin, has a total length of 13.6km. If contaminations should move in a rate of 0.27m/s, they would in 12 hours be able to reach the shore from a distance of 11.66km. Considering the fact that direction and speed of winds can have great local variations the data used is more of an indicator than anything else. If the wind reaches a speed of 10.5m/s and blows within 300-330° it is likely for contamination from anywhere within the bay to reach the shore within 12 hours. The safest way to form the zonation of the surface water would be to include the bay outside of the well within the primary zone for surface water.

All smaller lakes within a distance of less than 1km away from the bay of Sommen are included in the primary zone (figure 15). This short distance makes it very likely for contaminations occurring in the smaller lakes to reach the bay of Sommen in a very short time during spring flood events. Due to this fact not only the bay of Sommen in the surface water catchment area should be included in the primary zone but also the smaller lake surrounding the bay.

4.4 Calculating smallest area required supporting the well of Norra Vi It is hard to estimate the degree of influence the surface water of lake Sommen has on the groundwater without more physical investigation. One more theoretical method that can be used to get an indication to if the groundwater bearing layer and the lake is connected is to calculate the smallest surface area that is required to support the well with its daily groundwater flow. This area will be compared to the area of the catchment basin for groundwater. If the smallest area required is larger than the area of the catchment basin it indicates that parts of the groundwater is infiltrated from the lake (Naturvårdsverket, 2011). If, on the other hand, the smallest area required is smaller than the catchment basin there is not necessarily any infiltration from Sommen.

, = ! # 365 / 123 # 0.001

Where: A = Area in m2 Q = Daily water supply in m3/day GVB = Yearly amount of groundwater production in mm (Naturvårdsverket, 2011).

Assuming the precipitation, which is not evaporated or surface runoff, is infiltrated in the groundwater-bearing layer, the amount of water infiltrated is equal to the annual precipitation minus the annual evaporation and runoff.

17 Since the estimated potential draft of the well is considerably higher a separate calculation will be conducted using the potential draft of 315m3/day (Ingenjörsbyrån VIAK, 1958). Should the area required for the wells potential draft be larger than the area of the catchment basin this would indicate that there is a connection between the groundwater and the lake.

4.5 Value of the water resource It is important to estimate the value of a water resource since this can influence decisions that may have an impact on the water resource quality or use. There is today no recognized method for valuation of water resources, which complicates the valuation process. It is very hard to put a number on the value of a water resource, and therefore the value of this water resource will be classified in a scale from “no value” to “extremely high value” (Naturvårdsverket, 2002). The value of a drinking- water supply depends mainly upon demand, quantity and quality of the water, but also the level of effort and cost associated with finding a substitute water supply if the current one should be contaminated and unfit to use (Naturvårdsverket, 2011). In this valuation of the water resource only the groundwater resource will be taken in to account. For valuation of lake Sommen the whole lake should be included and not only the part within the surface water catchment basin. Ground and surface water does have a natural exchange, but for practical reasons these two will be looked upon as separate resources. In the valuation both financial and non-financial values will be looked at. The financial values are for example the cost associated with replacement of the water resource, and non-financial values are for example the biological importance or the waters esthetical or recreational value. The water resource of Norra Vi is only used for private households and does not support any industry, school or hospital. This lowers the usage value of the water resource (Naturvårdsverket, 2002).

4.6 Classification of hazards Threats are listed along with its potential cause and most vulnerable phases. Threats are then inventoried and classified after likeliness of occurrence and how severe consequences they may have on the water quality (Livsmedelsverket, 2007). The result is presented in a matrix where likeliness and consequence is classified from low to very high. Focus will be on the existing and potential threats possibility to affect the water quality before reaching the water treatment plant in this report.

A risk classification was conducted by VISS in 2008 for this catchment basin. The investigation was conducted from using a point system for different hazards. The scale ranged from 0-40, where <10 equals low risk for contamination and >40 equals a very high potential for contamination. The total point given to the catchment basin was 11, meaning its within the lower parts of the scale for moderate potential for contamination

In conclusion from the risk assessment from 2008 the water resource was considered to have a good chemical and quantitative future. Until 2015 no major risks where found to threaten the quality of the water in the catchment basin (VISS, u.d.).

4.6.1 Criteria for classification Classifications of hazards are based on the probability for a specific incident to occur along with the magnitude of consequence. The risk factor is defined as the product of probability of occurrence and magnitude of consequence for events. The events used in this risk classification are based on the previously preformed risk inventory (Naturvårdsverket, 2011). Table 3 shows the 4 different levels of classification and criteria regarding likeliness of occurrence, and table 4 shows the different classification and criteria for magnitude of consequence.

18

Probability Criteria

S1: Low probability a) Event never occurred before b) Event cannot be excluded c) Low probability that event will occur

S2: Moderate a) Event has occurred within the last 5 years probability b) Event is judged to possibly occur within 10-50 years from today. c) Moderate probability that the event will occur.

S3: High probability a) Event occurs yearly b) Event has or has been close to occur in the current facilities. c) Event is judged to possibly occur within 1-10 years from today. d) High probability that the event will occur.

S4: Very high probability a) Event is occurring in the current facilities. b) Very high probability that the event will occur.

Table 1. States different criteria for the 4 different stages for likeliness of occurrence for a hazard.

Consequence Criteria

K1: Small consequence a) Quality: Insignificant impact on water quality. No remarks according to drinking water provisions. b) Supply: Normal supply to users can be maintained.

K2: Moderate a) Quality: Temporary remarks which affect several users or consequence unusable water affecting occasional users. b) Supply: Brief pause of delivery (few hours) to a limited area. No vulnerable users are affected. K3: serious a) Quality: Unusable water affecting many users. consequence b) Supply: Long-term interruption (days) in a limited area. Vulnerable users are affected K4: Very serious a) Quality: Unusable water with danger for health and life. consequence a) Supply: Long-term interruption affecting a number of users. Vulnerable users are affected.

Table 2. The four different classifications of consequence are listed along with its criteria.

19 4.6.2 Risk matrix for hazardous events After deciding likeliness and consequence for an event it is placed in a risk matrix (see table 5). The different colours given in the matrix has the following meaning (see table 4 for colour classification):

Black: Acute risk- Prevention and/or preparation measures must be taken and preformed immediately.

Red: Risk has to be reduced - Prevention and/or preparation measures must be taken and preformed as soon as possible.

Yellow: Active risk management - Prevention and/or preparation measures should be considered.

Green: Simplified risk management – prevention preparations should be maintained (for example regular checks and deviation management)

Consequence Likeliness K1 K2 K3 K4 Low Moderate High Very high

S4 – Very high Green Yellow Red Black

S3 – High Green Yellow Red Red

S2 – Moderate Green Green Yellow Red

S1 – Low Green Green Yellow Yellow

Table 3 shows the risk matrix with its different colour classifications.

5. Results

5.1 Local geology and hydrology Test drilling in this area has resulted in several soil stratigraphies (Ingenjörsbyrån VIAK, 1958). Figure 8 shows the location of the three cross-sections that has been created from the drilling. Cross section 1 and 3 are made in an E-W orientation, and 2 in an N-S direction. The holes were drilled down to 9 or 12 meters, and grain size analyses were done with an interval of 3 meters. Where data of the groundwater level was accessible this is also plotted in the stratigraphy.

20

Figure 8. The map shows the location for the three different cross-sections.

Figure 9 shows cross-section 1, which stretches along the shore of lake Sommen in an E-W direction. The four boreholes all show a gradual transition in grain size with depth. The uppermost meters consist of a silty fraction, with a transition in to sand further down. Below the sand the fraction is even coarser, and dominated by gravel. The groundwater table is located in the transition-zone between the sandy and silty material. The well, which is currently in use, is located at borehole 5. This drill hole is the one, which due to the topography, is closest to the groundwater table. Figure 10 shows a transect going from north to south, with a start at the shore of lake Sommen. South of the lake the elevation is higher, and there is coarser till to be found at depth in the drill holes. Figure 11 is a transect going from west to east a few hundred meters south of the well. This shows thinner soil coverage in general going south from the lake. The point furthest to the east in the cross section is not based on the drill hole data but rather on the soil mapping shown in figure 4. This figure shows that the till is visible at the surface to the east, but then disappears under ground towards the west.

21

Figure 9. Cross-section 1 goes parallel to the shore of lake Sommen, in an E-W orientation. It also shows the groundwater levels in the different holes.

Figure 10. Cross-section 2 starts at the shore of lake Sommen in north, and stretches south. It shows the groundwater level at lake Sommen and the first drill hole, which is the well currently in use.

22

Figure 11. Cross-section 3 stretches from west to east, approximately 350 meters from the shore. The fist two drill holes shows a thin sedimentary layer before drilling in to hard rock. The point furthest to the east is based on soil mapping shown in figure 4. 5.2. Catchment basins for groundwater The catchment basin for groundwater is approximately 0.45km2 and outlined in figure 12.

Figure 12. Topographical map over Norra Vi. The red line shows the suggested catchment basin for the groundwater.

23 5.3. Zonation for groundwater catchment basin The average discharge for the well is 40m3/day (Norra Vi Vattenverk, 2008). As previously mentioned the boundary between the primary and secondary zone is where the groundwater resident time exceeds 100 days. Therefore t = 100 in the calculation of the primary zone and t= 365 for the secondary zone. The deepest drilled area drilled below the groundwater table was 10 meter. Without knowledge of how deep the groundwater bearing layer is in average an assumption of 10 meters will be used for the purpose of this calculation. The kinematic porosity for different materials will be used to calculate the smallest potential radius as well as the largest potential radius for that specific soil type (Gupta & Singhal, 2010).

Min. Radius in Radius in Max. Radius in Radius in kinematic m for m for kinematic m for m for Sediment porosity primary secondary porosity in primary secondary type in % zone zone % zone zone Gravel 15 29.14 55.68 30 20.61 39.37 Sand 10 35.69 68.19 30 20.61 39.37

Table 4. The smallest and largest potential areas for the secondary and primary zone of the groundwater-bearing layer.

The groundwater-bearing layer does mainly consist of sand and gravel (see figure 9-11), and therefore the most conservative numbers for these two sediment types will be used when creating the zonation of the area (see figure 13).

24

Figure 13. The map shows the zonation of the groundwater area. The primary zone (the inner circle) has a radius of 36 meters from the well, while the secondary zone stretches 32 meters from the boundary of the primary zone.

5.4 Catchment basin for surface water The area of the catchment basin for the surface water is approximately 1910km2 (Figure 14) (SMHI 2., u.d.). The northern part of the catchment area is within Boxholm municipality. Parts of Sommen are already incorporated in existing water protection areas for other wells located along the shores, as well as for water being pumped from the lake and used as drinking water (Länsstyrelsen, u.d.; Länsstyrelsen Västra Götalands Län, u.d.)

25

Figure 14. The catchment basin for surface water has a total area of 1910 square kilometers and covers large areas of Östergötland (SMHI 2., u.d.). 5.5 Zonation for surface water catchment basin The zonation of the surface water is displayed in figure 15. This area includes the bay of Norra Vi and the small lakes in close proximity.

26 Zonation of catchment basin for surface water

m

&

Kilometers 0 1 2 3 4 Legend

& Location of well Primary zone

Figure 15. Map showing the zonation of surface water catchment basin.

27 5.6 Calculating smallest area required to support the well of Norra Vi The closest weather station measuring precipitation is located in Norra Vi (serial number 7554) and had an average annual precipitation of 586.9mm/year between 1961-1990 (SMHI 1., u.d.). The average yearly groundwater recharge is, according to VISS estimations, 290mm/year (VISS, u.d.). This means that approximately 50% of all precipitation is either evaporated or transported as surface water. The average withdraw of water from the Norra Vi well is 40m3/day (Norra Vi Vattenverk, 2008). This means that the average yearly water supply is:

! = 4083/9:; ! ∗ 365 = 14 60083/;=:'

The yearly water supply is then divided with the infiltration per square meter to get the total area required.

123 = 0.298/;=:'

1460083 , = 0.298

, = 50 34582

The area required providing the well with its yearly water supply is 50345m2, or 0.05km2.

The estimated potential draft for the well of Norra Vi is 315m3/day (Ingenjörsbyrån VIAK, 1958). If the well were utilized with its full potential draft, the yearly water supply would then be:

! = 31583/9:; ! ∗ 365 = 114 97583/;=:'

The yearly water supply is then divided with the infiltration per square meter to get the total area required.

114 97583 , = 0.298

, = 396 46582

The area required providing the well with its potential yearly water supply is 396 465m2, or 0.39km2.

5.7 Value of water resource The value of the current water reservoir in Norra Vi is estimated to be low from following arguments:

• It supplies a small area with drinking water and less than 60 people. • The water resource is only used for private households. • The groundwater resource does not have esthetical or recreational value. • In the area there is a big reservoir of groundwater and several other localities has proven to be adequate (Ingenjörsbyrån VIAK, 1958). The well is therefore assumed to be retrievable. • The cost associated with replacement of the well is considerably high due to the small size of the municipality and the low number of people it is supplying with water.

28 5.8 Classification of hazards

5.8.1 Summary of hazardous events and vulnerable states In table 2 all the different threats are listed along with unwanted event, source of pollution and its vulnerable stats. This is a summary of the different threats, which have been explained more in detail in previous sections.

General event Unwanted event for water Sources Vulnerable states supply Installing energy Leakage of oil and other From vehicles and During installation of wells (and other liquids used in the pump equipment a heat pump construction work) system or used during installation

Energy wells Leakage of chemicals from Damaged polythene If energy wells are the polythene tubes tubes installed too close to each other and temperature in the ground drops below 0°C Local industry - Mobility of potential Chemical leachate If the area is flooded Visskvarns träsliperi chemicals in the soil if the area was used mobility may to store chemicals increase Use of pesticides on Chemicals from pesticides Use of pesticides, If there is a lack of pathways in the moves down quickly since both today and permeable layer graveyard gravel is extremely previous usage underneath the gravel permeable paths and if groundwater surface here is shallow Burial or spreading Mobility of heavy metals Decomposing If bodies are buried of ash associated with spreading bodies and ash in unsealed caskets, of ash and increased heavy especially less than 1 metals and organic matter meter from the associated with burial groundwater table, or if ash is spread close to groundwater table Use of fertilizers for Leaching from artificial Substances used in Agricultural land agriculture fertilizer infiltrates the fertilizers within the watershed ground and is transported to the water discharge area Use of pesticides for Leaching of pesticides Substances used in Agricultural land agriculture infiltrates the ground and is pesticides within the watershed transported to the water discharge area Irrigation on Increased mobility of From excess use of Agricultural land agricultural land pesticides and fertilizers in water within the watershed soil

Deforestation Increased runoff may rise Deforested areas Deforestation of levels of organic matter, existing woodlands lower pH and act as in the surroundings nutrient for bacteria of Norra Vi

29 Short term storage Chemical substances’ Non-wanted Several woodlands of wood after leaching from the bark is chemical are located in the deforestation within infiltrated and reaches the substances are surroundings of the watershed groundwater. found in the bark Norra Vi Forestry and other Leakage of fuel from Spillage and Several woodlands work with heavy vehicles and machines used accidents causing are located in the machinery during deforestation, damage to fuel surroundings of infiltrating and transported tanks. Norra Vi to the groundwater reservoir. Ditching and other Leaching of nutrition from Alternation of the Several woodlands work with heavy the surrounding grounds, natural ground- are located in the machinery and spillage of petroleum conditions can give surroundings of products from machines a higher rate of Norra Vi performing the ditching. runoff as well as Enhanced concentration of lead to a change in these substances makes the soil chemistry. water unfit to drink. Farm animal waste The faeces from farm Waste from farm Suitable fields for animals may pollute the animals if kept in a grazing in Norra Vi. soil and groundwater with limited area viruses, bacteria, nitrogen and chloride Burial of cattle If large number of animals Decomposing Suitable fields for are buried at the same place bodies grazing in Norra Vi. the groundwater may be contaminated when the bodies decomposes Old landfill Leaching of contaminants Chemical Old landfill is found infiltrates the ground and is substances in old in Norra Vi transported to the public landfills water discharge area Road salt on road Chloride and other Traffic safety Road 561 passes 561 substances infiltrate the through ground and gets transported to the water discharge area Traffic accident on Contaminants infiltrate the Punctured tanks Road 561 passes road 561 involving ground and is transported to leading to leaking through propellant. the water discharge area of propellant/ and or oil Traffic accident on Contaminants infiltrate the Damaged and Road 561 passes road 561 involving ground and is transported to punctured tanks through hazardous cargo. the water discharge area containing hazardous substances Climate change Increases the risk for Increased rainfall Current flooding and submersion, contaminated areas which may lead to spreading of contaminants. There is also potential for an increase in erosion and leaching of nutrients.

30 Private sewages Bacteria and Nutrition, Leaking from Use of private mainly as phosphor, can private sewages sewages leak from private sewages and contribute to over- fertilization of the ground Boats in Sommen Leakage from engines of Mainly small The close proximity from loss of extra cans of private boats of lake Sommen petrol Oil tanks Leaks of oil and chemicals Tanks stored in and Farmlands using fuel can release unwanted on ground and chemicals from substances tanks

Table 5. A summary of potential threats to the water quality is listed in the table, stating the unwanted events, source of pollution as well as its vulnerable states.

5.8.2 Risk matrix for hazardous events Event Probability Consequence Risk-factor Installing energy wells S1 K1 Green Energy wells S2 K2 Green Local industry - S1 K1 Green Visskvarns träsliperi Use of pesticides on S3 K2 Yellow pathways in the graveyard Burial or spreading of S1 K2 Green ash Use of fertilizers for S3 K3 Red agriculture Use of pesticides for S2 K3 Yellow agriculture Irrigation on S3 K2 Yellow agricultural land Deforestation S2 K2 Green Short term storage of S2 K1 Green wood after deforestation within the watershed Forestry S1 K1 Green Ditching S1 K1 Green Farm animal faeces S1 K2 Green Burial of cattle S1 K1 Green Old landfill S1 K2 Green Road salt on road 561 S1 K2 Green Traffic accident on S1 K2 Green road 561 involving propellant. Traffic accident on S1 K3 Yellow road 561 involving hazardous cargo. Climate change S2 K1 Green

31 Private sewages S1 K2 Green Boats in Sommen S2 K2 Green Oil tanks S1 K2 Green

Table 6. Events are listed in a risk matrix, showing the risk factor for the occurrence of a single event.

6. Discussion

6.1 Local geology and Hydrology

6.1.1 Geological and Hydrological conditions of Norra Vi The glacifluvial sediment at the shore of Norra Vi consists mainly of silt, sand, gravel and till. The topsoil layer of the study area is comprised mainly of silt, with some areas having a combination of silt and sand, and with an overall shift to coarser sediments at depth (see figure 9-11). The relatively high effective porosity displayed in the uppermost layers (kinematic porosity of 5-30%, see table 4) makes it likely to assume that recharge of the groundwater occurs from precipitation falling straight above and that surface runoff is limited (Grinevskii & Novoselova, 2011). Test pumping conducted in 1958 showed a more or less instant correlation with precipitation and water levels in the different test holes (see appendix 2) (Ingenjörsbyrån VIAK, 1958). This correlation with precipitation and increased water levels indicates that water is recharged in a nearby area, supporting the theory of recharge from precipitation occurring from the surface above. This assumption can be made considering a slower reaction to precipitation fluctuations would prevail if recharge occurred further away from the test holes. At bore hole number 5, where the well is located, the uppermost layer of soil consists of a combined topsoil of sand and silt, creating higher permeability compared to other boreholes where the topsoil layer consists only of silt. This shows that the permeability of the topsoil is the highest in the area with closest proximity to the well. The lack of a less permeable layer, as for example clay, makes the groundwater flow more easily and increases the sensitivity for contaminations, as there is no natural barrier preventing contaminations of spreading (Rumer & Ryan, 1995).

6.1.2 The relationship between the groundwater reservoir and lake Sommen As seen in cross section one and two (figure 9 and 10) the water table of the lake and the groundwater table along the shore is found at the same elevation, displaying a strong correlation between the lake and the groundwater table. This strong correlation supports the theory of the lake and the groundwater to be interconnected. Correlations between groundwater flow, precipitation and water tables of lakes are seen in areas with less permeability compared to the one of Norra Vi (Lee, 2000), indicating that a strong correlation between groundwater table and lake surface table in this setting is to be expected. It is likely for the deeper layers of sediment, which has the potential for the highest flow rates, to be in direct connection with the lake. This would both explain the high potential discharge of the well and the quick recovery of the groundwater table experienced after test pumping commenced in 1958 (see appendix 2).

As seen in appendix 2 a drop in groundwater table occurred in all measured test holes when test pumping commenced. The groundwater table recovered shortly after the initial drop in all holes apart from at hole number 5, which is the hole located closest to the pump. This is likely the result of a cone of depression forming around the pump, since water in the immediate surrounding is drawn in to the pump (see figure 16). It is also visible that the groundwater level did not recover at hole number 5 once test pumping was completed within the measured timeframe. If the water table had been

32 measured for a longer period of time after pumping was finished it would most likely have recovered to its original level. Since the water table in all other bore holes apart from number five recovered quickly after pumping commenced, it is likely that the cone of depression forming around the pump was fairly limited in size, as it otherwise would have impacted the groundwater level of the other measuring sites. Had the pumping occurred in an area with lower kinematic porosity the cone of depression would have been steeper as a result of a more significant drawdown (Bloetscher, 2014).

Figure 16. The image shows how the cone of depression impacts the groundwater table (Ami Adini & Associates, Inc. Environmental Consultants, 2011).

Another indicator suggesting a connection between the groundwater and the lake is the water quality samples taken in 2005, which displayed elevated levels of turbidity in the groundwater (Norra Vi Vattenverk, 2008). Higher levels of turbidity is unusual in groundwater that is not in direct connection to surface water (Sophocleous, 2002), which indicates that the higher turbidity could be a result from inflow of water from lake Sommen.

6.1.3 The possible occurrence of a groundwater divider A groundwater divider can be a result of either difference in topography or difference in permeability, and results in water having different direction of flow on the different sides of the divider (Nonner & Nonner, 2002). In cross section 2 (figure 10) the southernmost hole, drill hole number 3, shows layers of gravelly and blocky till at depth. This layer of sediment is found at almost the same elevation as the groundwater table in hole number 5 (and therefore also at the same elevation as the lake). This layer of till stretches in an east-western direction, as seen in cross section 3 (figure 11). Till is many times a less permeable material (Gupta & Singhal, 2010), compared to the otherwise commonly prevalent gravel and sand in the area, since it consists of many different grain sizes, where the smaller grains often fill the gaps between the coarser fractions, limiting water flow. The result of this difference in permeability creates the possibility of the prevalence of a groundwater divider. An example of a groundwater divider can be seen in figure 17, where water has a different direction of flow on the different sides of the hill.

33 6.2 Catchment basins and zonation for groundwater The catchment basin for the groundwater is previously mentioned based on the assumption of the prevalence of a groundwater divider. There are two theories supporting this assumption. The first being that the less permeable till found south of the well (see figure 11) acts as a groundwater divider, preventing water here from flowing in a south-north direction. The second theory is that the nearby stream (see figure 12) acts as a discharge area as described in figure 17. Water from the eastern side of the height curves in figure 12 is therefore assumed to flow towards the nearby stream and not towards the well.

Figure 17. Groundwater in the area near the stream is being discharged in to the stream (U.S Geological Survey, 2014).

The assumption of the prevalence of a groundwater divider used in this report needs to be verified through pumping. If the assumption is wrong and there is no water divider the catchment basin for the groundwater could potentially be significantly larger. This would not have an impact on the boundaries of the primary and secondary protection zone, but could have a large impact on the formation of the tertiary zone. Due to the fact that no limitations or restrictions will be implemented for the tertiary zone the size and shape of the tertiary zone is of less importance, compared to the primary and secondary zone. But due to the uncertainty of groundwater flow direction any contamination occurring within a few kilometres radius of the well should be monitored to assure that it does not reach the well until further investigations have been conducted and the groundwater flow direction has been established.

The method used for calculating the zonation of the groundwater catchment basin is a general calculation and does therefore only provide a rough estimation. To enable a more accurate estimation of the groundwater flow velocities more data is required, as for example data regarding the gradient of the groundwater flow, depth of the groundwater bearing layer as well as more knowledge of the kinematic porosity and local variations. This data can only be required through field-testing. The calculation used does only determine the area affected by pumping and assumes there to be no natural flow of groundwater. For the purpose of this thesis several generalizations and estimations had to be made for this calculation. Some obvious

34 shortfalls in this calculation are the lack of a gradient of flow, an assumed homogenous mass of sediment as well as an assumed radial flow of water. In reality it is likely for there to be a more prominent direction of flow (Nonner & Nonner, 2002), making the shape of the primary and secondary zone not completely circular in shape. Since the gradient and direction of water flow is unknown it is not possible to eliminate any flow of direction, which is why the assumption of a radial flow had to be made.

6.3 Catchment basin and zonation for surface water The catchment basin for lake Sommen was taken from SMHI Vattenwebb. The catchment basin consists of 1910km2 and includes several lakes, most of them located southwest of Sommen. Due to the extremely large are of the catchment basin there will be no limitations or restrictions put in place apart from within the primary zone. It was therefore decided to only divide the surface water zonation in to two zones, one primary and one secondary zone. The primary zone is based on estimated transportation times in the lake using the strongest likely wind speed in the most vulnerable direction (300-330°). The result of this calculation showed that the bay of Norra Vi should be included in the primary zone (see figure 15). There area several smaller lakes and streams with outlets directly in to the bay of Norra Vi. Due to time restrictions and practical limitations it was not possible to make separate calculations for all the individual streams. Therefore, as a precaution, all the lakes and streams with outlets in the bay were included in the primary zone.

The greatest weakness of this calculation is the lack of data from the study area due to the nearest wind station being located 30 km from Norra Vi. Wind can display great local variations, and an open area, as for example the bay, can show significantly higher wind speeds depending on wind direction (Johansson & Chen, 2003). There are therefore possibilities for the wind data used to be inaccurate, and therefore the primary zone might be underestimated.

6.4 Calculating the smallest area required to support the well of Norra Vi Calculating the smallest area required for the well to be supported with its daily flow of water can be used to get an indication to if there is any direct connection between the groundwater and the nearby lake. It is important to note that this calculation only gives an indication of weather a connection to another water body is necessary for the supply of groundwater, and will therefore not be able to exclude the prevalence of a connection. Since there is no direct evidence for the lake and the groundwater body to be in direct connection this calculation was used as a tool to help estimating if a connection to the lake is likely. The aim with the calculation is to compare the area received through the calculation with the area of the catchment basin. The calculation resulted in an area of 0.05km2 being required to support the well. Since the area required providing the well with its daily water supply is significantly smaller than the catchment basin of 0.45km2, the groundwater bearing layer and the lake does not necessarily have to be connected. When comparing the potential draft of water of at least 315m2/day, the smallest area required is 0.39km2, and therefore also smaller than the catchment basin. Should the area have been larger than the catchment basin for groundwater a connection between the lake and the groundwater body would have been very likely, since there otherwise would be no possibility for the catchment basin to provide the well with the current potential draft of water on its own (Naturvårdsverket, 2011). The potential draft of 315m2/day is only a potential minimum, and the actual potential discharge from the well might be higher than this (Ingenjörsbyrån VIAK, 1958). Should the potential discharge from the well be significantly larger than the today estimated 315m2/day the calculation could result in a lake and groundwater connection to be very likely. A connection between the groundwater reservoir and lake Sommen can from this calculation either be

35 excluded or confirmed, and this is merely one method of testing the probability of a connection between the two water bodies.

6.5 Value of water resource It is very hard to determine an exact value for a natural water resource, and therefore this water resource has only been classified on the scale of “no value” to “extremely high value” in accordance to Naturvårdsverket. The value of the water resource was classified as low based on the arguments mentioned under section 5.7 in this report. The main reasons for the well to be classified as having a low value is because the water resource is easily replaced and it supports a low number of people. Even though the water resource value was classified as low it does not mean that the resource should not be protected. Not only since there is a cost associated with replacement and that a contamination of the water does probably have biological impacts, but mainly to protect the people that uses this resource for drinking water. If surface water were to be accounted in the valuation the value of the resource would be classified significantly higher due to its biological, esthetical and recreational value. The value of a water resource can be changed with time when one or several factors used in the estimation changes. A sudden growth of population in the area or changed conditions can lead to an increased value of the water resource. One of the current threats we are now facing is climate change, which can have a significant impact on the amount or precipitation received in certain areas. Should climate change lead to a decreased precipitation and higher average temperatures water would become scarcer, therefore increasing the value of the water resource and thereby increasing its need for protection (Hundloe & Crawford, 2012).

6.6 Threats facing the groundwater quality In contradiction to the investigation conducted by VISS (VISS, u.d.) this study found several potential threats facing the groundwater quality in the area of Norra Vi. Only few of these are shown to pose a moderate threat and none shows to pose a high threat. Over all a groundwater resource with a high recharge is often associated with increased vulnerability, since a high flow of water leads to higher mobility of contaminants (Healy, 2010). The somewhat high precipitation experienced in the region in combination with a recharge from the surface straight above creates a shorter timeframe before any contamination reaches the well. Even though the severities for most of the threats are considered to be low it does not mean that there are no existing threats. In the following section recommended preventions will be listed, which main goals are to minimize the potential for certain incidents to occur and to minimize the severity if a certain event does occur.

6.7 Potential prevention measures In table 6 the possible events mentioned previously that might harm the water quality are listed with potential prevention measures. These are only recommendations and some might be found to be too expensive or too circumstantial for implementation.

36

Event Potential prevention Energy wells • No drilling within the water protection area • Refill or seal old boreholes close to water protection areas Local industry - • Check for contamination in ground and treat if necessary Visskvarns träsliperi Use of pesticides on • No use of pesticides in the water protection area pathways in the • If the groundwater table is close to the surface make sure to have an graveyard impermeable layer underneath the gravel if harmful chemicals are used Burial or spreading of • Make sure to bury caskets with a 1 meter distance from the ash groundwater table Use of fertilizers for • No use of fertilizer within the primary zone for groundwater agriculture • Use biodegradable products in the secondary zone for groundwater Use of pesticides for • Prohibit the use of pesticides in the primary and secondary zone or agriculture use environmental friendly products and methods Irrigation on • If no harmful chemicals are used in pesticides or fertilizers agricultural land irrigation should not be a problem Deforestation • Do not clear large areas of forest at one time • Install turbidity alarm in sensitive areas Forestry • Make sure equipment does not cause any oil-spillage Ditching • Avoid ditching if possible • Install turbidity alarm in sensitive areas Burial of cattle • Large quantities of cattle should not be buried in the same place Old landfill • Sanitise any potential chemical contamination • If there is risk for leakage a warning system should be put in place as well as regular checks for leakage Road salt on road 561 • No precautions has to be taken here apart from regular quality controls of the drinking water Traffic accident on road • Install speed cameras if necessary 561 involving • Potential lowering of speed limits propellant. • Increased road quality Traffic accident on road • Install speed cameras if necessary 561 involving • Potential lowering of speed limits hazardous cargo. • Increased road quality Climate change • If rainfall is increased in long terms the borders for the present water protection area may have to be revised Private sewages • If there area any private sewages these should be checked for leakages or failures Boats in Sommen • Limit the amount of petrol that can be taken aboard on the boat. • No re-filling of petrol within the water protection area • Create a barrier along the shore of Sommen to prevent contaminated water from the lake to reach the well Oil tanks • Oil tanks and tanks for storage of chemicals should be checked for leakage or failures

Table 7. Events with suggested prevention measures.

37 7. Conclusion Threats posing this groundwater reserve are considered to be relatively low, and the groundwater resource itself is of value. This does not mean that there are no threats to be taken in to consideration or that the groundwater resource should not be protected. The areas for the primary and secondary zone in the groundwater catchment basin are fairly small and therefore implementations of recommended preventions should be put in use here without any extensive costs. If these recommendations are followed up there is no immediate threat to the groundwater quality and no major occurrences affecting the groundwater quality should be expected in the nearest future, if conditions stays the same. Fencing of the primary zone for the groundwater catchment basin (a radius of 30 meters from the well) would minimize the likeliness of any event occurring that could have a negative impact on the groundwater quality and for which there would not be sufficient time given to take any actions. To ensure the accuracy of the groundwater catchment basin concluded in this report a drilling program is required. This is recommended since a better understanding of the catchment basin makes it easier to predict the flow of groundwater and therefore the likely spread of a potential contamination.

Since the groundwater body is believed to be in direct contact with the lake and for this connection to be located in an area with high permeability it is important to assure good water quality in the lake. Due to the very large size of the lake and the fact that there is boat traffic in nearby areas this can potentially be hard to ensure. Therefore implementation of a warning system near the shoreline or a man made barrier can be considered to ensure groundwater of good quality. It is highly recommended for the relationship between ground- and lake water to be further analysed before implementing a barrier.

8. Acknowledgement I want to thank Daniel Glatz at Hifab AB for guidance through this report and all the long hours of conversations. I would also like to thank the Department of Earth Sciences, University of Gothenburg for this opportunity.

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Appendices

Appendix 1

Appendix 2