Maakasutuse ja kliimamuutuse mõju Eesti jõgede hüdroenergeetilisele potentsiaalile

A Thesis for applying for the degree of Doctor of Philosophy in Engineering Sciences.Water-related changes are currently receiving the most focus in the context of climate change around the world. The changing climate conditions have already redistributed water resources, including the hydropower potential in Estonian rivers. This phenomenon is expected to continue in the future. However, the effects on land use and climate change on the hydropower potential in Estonia are unclear. The technical hydropower potential was assessed for the territory of Estonia (excluding the Narva River). According to the developed method, the total technically feasible hydropower potential in Estonia was calculated to be approximately 80 MW, which was considerably higher than that previously reported. The SWAT model was employed to assess the potential impact of future climate and land-use change on river flow in various Estonian river watersheds, where hydropower is or has been harvested. The SWAT model demonstrated satisfactory performance in describing the hydrological processes in Estonian rivers by using series of mathematical equations. An evident linear trend between the effects of deforestation and afforestation on yearly river flow was observed. The following general rule can be applied to Estonia; a 5% forest change induces a 1% change in annual average flow. Hydrological modeling indicated a positive change in river flow according to both climate scenarios. Increases in the mean annual flow of 10% and 33% were predicted by the climate projections KNMI and DMI, respectively. Hydropower potential is expected to increase in Estonia by the end of the century, compared with the baseline period. The installation of additional turbines, along with upgrading existing turbines, could increase the installed capacity. Furthermore, with the projected overall increase of hydropower potential in Estonia, the construction of new stations becomes more economically feasible and profitable.Veeressursidega seonduvad küsimused on viimastel kümnenditel olnud ülemaailmselt üks huvipakkuvamaid temaatikaid teadlaste seas. Seda just seetõttu, et vee ajaline ja koguseline kättesaadavus on kliimamuutuse tõttu muutumas, mis on mõjutanud ka Eesti jõgede hüdroenergeetilist potentsiaali. Nende muutuste jätkumine avaldab mõju ka hüdroenergia tootlikkusele, ent kui suuresti võib Eesti jõgede hüdroenergeetiline potentsiaal muutuda, on teadmata. Doktoritöös antakse uus hinnang Eesti (v.a. Narva jõe) tehniliselt rakendatavale hüdroenergeetilisele potentsiaalile. Selleks tuletati meetod, mille kohaselt Eesti jõgede tehniline hüdroenergeetiline potentsiaal seni hinnatust märkimisväärselt suurem, olles ligikaudu 80 MW. Maakasutuse ja kliima muutumise mõju Eesti jõgede vooluhulkadele hinnati hüdroloogilise mudeli SWAT abil, kalibreerides ja valideerides seda Eesti suurema hüdroenergeetilise potentsiaaliga jõgedele. Selgus, et SWAT- mudel suudab piisava täpsusega matemaatiliselt kirjeldada Eesti jõgedes kulgevaid looduslikke protsesse. Ilmnes tugev lineaarne seos metsasuse ja aastakeskmise vooluhulga muutuse vahel. Seda seost võib üldistada järgmiselt: metsasuse viieprotsendine muutus muudab jõe aastakeskmist vooluhulka 1 % võrra. Kliimamuutuse mõju Eesti jõgede aastakeskmisele vooluhulgale on positiivne — olenevalt kasutatud kliimamudelist 10 kuni 33 protsenti. Hüdroenergeetiline potentsiaal on Eestis suurenemas. Selle positiivse mõju ärakasutamiseks on soovitatav olemasolevaid hüdroelektrijaamu laiendada või uuendada. Eesti jõgede hüdroenergeetilise potentsiaali suurenemine teeb uute hüdroelektrijaamade rajamise majanduslikult otstarbekaks.Publication of this dissertation is supported by the Estonian University of Life Science

Programmi RITA tegevuse 1 projekti „Varustuskindluse tagamine toidu, esmatarbekaupade, isikukaitsevahendite ja vee tarneahelas Eestis“ lõpparuanne

Uuring valmis Majandus- ja Kommunikatsiooniministeeriumi, Rahandusministeeriumi, Sotsiaalministeeriumi, Siseministeeriumi, Kaitseministeeriumi, Maaeluministeeriumi ja Riigikantselei eesmärkide elluviimiseks.Lõpparanne täieneb aja jooksul. Käesolev versioon on seisuga 30.03.2022.Käesolev aruanne võtab kokku uuringu „Varustuskindluse tagamine toidu, esmatarbekaupade, isikukaitsevahendite ja vee tarneahelas Eestis (VARUST)“ olulisemad järeldused. Uuringut rahastati Eesti Teadusagentuuri Euroopa Regionaalarengu Fondi programmi „Valdkondliku teadus- ja arendustegevuse tugevdamine“ (RITA) tegevusest 1 „Strateegilise TA tegevuse toetamine“ (leping nr 7.2-2/20/24). Uuring valmis Majandus- ja Kommunikatsiooniministeeriumi, Rahandusministeeriumi, Sotsiaalministeeriumi, Siseministeeriumi, Kaitseministeeriumi, Maaeluministeeriumi ja Riigikantselei eesmärkide elluviimiseks. Uuringu viis läbi kolmest organisatsioonist koosnev konsortsium, kuhu kuulusid Eesti Maaülikool (3 töögruppi), Eesti Konjunktuuriinstituut ja Eesti Taimekasvatuse Instituut. Uuringu lähteülesande kohaselt oli uuringu eesmärgiks luua ettevõtetele toimepidevuse hindamiseks universaalne lähenemine (edaspidi mudel), pakkuda välja varustuskindluse mõõdikud ja sihttasemed ning pakkuda välja soovitused, kuidas korraldada varustuskindluse lahendamine Eesti oludele sobivaimal ja riigieelarvet ning ettevõtjaid vähem koormaval viisil.Uuringu tellis ja uuringut rahastas Eesti Teadusagentuur Euroopa Regionaalarengu Fondist toetatava programmi „Valdkondliku teadus- ja arendustegevuse tugevdamine“ (RITA) tegevuse 1 „Strateegilise TA tegevuse toetamine“ kaudu

Modelling of the hydroenergetical potential of River Kunda

SWAT mudeli kasutatavuse hindamine Kunda jõel ja vooluhulkade modelleerimine SWAT mudeliga. Saadud tulemuste järgi analüüsida, kuidas tuleviku vooluhulkade muutus mõjutab Kunda jõe hüdroelektrijaamade tootlikkust. Töö eesmärk on modelleerida SWAT mudeliga vooluhulgad Kunda jõele ja nende kaudu arvutada hüdroenergeetiline potentsiaal tuleviku perioodile 2011-2099, Kunda tsemenditehase hüdroelektrijaamas. Töös kasutati EMHI-st saadud järgmisi andmeid: sademed, temperatuur, tuul, päikesepaiste kestus, õhuniiskus. Veel kasutati kõrguskaarti, maakasutuskaarti, mullakaarti. Kasutatavad programmid oli SWAT ja SWAT-CUP. SWAT mudeli järgi modelleeriti esialgne lahendus, mis aga ei olnud piisavalt tõhus. Seega kalibreeriti parameetrite vahemikud programmiga SWAT-CUP. Kalibreeriti perioodile 1972-1984 ja 1985-1997, ning valideeriti perioodile 1998-2010. Tõhusamaks osutus esimesel kalibreerimisperioodil saadud parameetrite vahemik. Antud vahemikke kasutades saadi valideerimisele NS tõhususe arv 0,60, mis tähendab töötavat mudelit. Kasutades kliimamuutuse stsenaariumi, modelleeriti vooluhulgad perioodile 2011-2099. Vooluhulkade järgi arvutati Kunda jõele hüdroenergeetiline potentsiaal. Kasutades hüdroloogia mudelit SWAT, modelleeriti tõhusalt Kunda jõe vooluhulgad. Hüdroenergeetilise potentsiaal kasv arvutatud HEJ-s tõusis perioodi lõpuks 0,25 GWh võrra, mis tähendab üle 10 protsendilist kasvu. Seega võib päevakorda tulla neljanda turbiini lisamine tsemenditehase hüdroelektrijaamale, mille võimsus võiks olla 48 kW.Evaluating SWAT model applicability in Kunda river and modelling flows with SWAT model. Analysing how predicted flows in the future affect the Kunda river hydropower plant productivity. Thesis objective was to model Kunda river flows to Kunda cementfactory hydropower plant for period 2011-2099. Following weather data from EMHI was used: precipitation, temperature, wind, sunshine duration. Additionally digital elevation map, land use map and soil map were used. Programs SWAT and SWAT-CUP were used. Initial SWAT model solution wasn’t efficient enough. SWAT model parameter ranges were calibrated with SWAT-CUP. Periods 1972-1984 and 1985-1997 were calibrated and validated against periood 1998-2010. First calibration periood was more efficient. Using given ranges model was validated, NS efficieny was 0,60, which means a working model. Flows where modelled to periood 2011-2099 using given climate scenario. Hydroenergetical potential to Kunda river was calculated from flows. By using hydrology model SWAT, flows were modelled efficiently for Kunda river. Hydroenergetical potential growth in the used hydorpower plant rose 0,25 GWh by the end of the periood, which means a raise of over 10 percent. Thus installing a fourth turbine to the cementfactory hydropower plant, having a 48 kW capacity, may come to agenda

KIK projekt nr. 15589

Läänemere äärsetes riikides on eelmisel sajandil tuvastatud statistiliselt oluline kliima soojenemine. Aasta keskmine õhutemperatuur on tõusnud nii Eestis (Jaagus 2006; Kont jt. 2007) kui ka naaberriikides: Lätis (Lizuma 2007), Soomes (Tietäväinen jt. 2009), Venemaal (Anisimov jt. 2011), Rootsis (Alexandersson 2002). Õhutemperatuuri tõusuga seonduvalt on suurenenud valingvihmade intensiivsused ja lühialalisi sademethulkasid, mis omakorda on põhjustamas üha enam lokaalseid uputusi Eestis. Mida kõrgem on õhutemperatuur, seda rohkem veeauru õhku mahub. Seega saab atmosfääris veeauru kondenseerumisel tekkida näiteks suuri rohkelt sademetevett sisaldavaid rünkasajupilvi, mis võivad suhteliselt klokaalselt intensiivsete sademetena maha sadada. Mida intensiivsemad on sademed ja lühiajaliselt allasadava valingvihma hulk, selle suurenemine näiteks tulevikus, seda suurem on ka koormus sademeveesüsteemidele. Kliimamuutusest tuleneva mõjudega kohanemine on Eestis üks tähtsamaid keskkonna probleeme, millega riik on viimastel aastatel tegelenud. Kuigi kliimamuutusest tingitud valingvihmade suurenemine on vähemalt lailadase meediakajastuse tõttu ilmne, puudub hetkel Eestis arusaam, kui palju ja kas valingvihmad on intensiivsemaks läinud. Sademeveesüsteemi projekteerimisel lähtutakse senini Eesti Vabariigi standardist 848:2013 «Väliskanalisatsioonivõrk». Standardi arvutusvihmade koostamisel on kasutatud meteoroloogiajaamade andmeid, mis on pärit eelmise sajandi esimesest poolest. Mõõdetud andmed lõppevad aastal 1961, seega on arvutusvihmad ligi 60 aastat vananenud ja arvutusvihmade koostamise metoodika ei vasta tänapäevasele metoodikale. Kehtiv standard ei arvesta kliimamuutuste mõjuga. Lisaks kliimamuutusele on suurenenud sademeveesüsteemide hüdrauliline koormus tänu kõvakattega pindade ehitamisele sademeveesüsteemi valgaladele. Eestis algas linnastumine 19. saj teisel poolel, intensiivistus alates 1950ndatest, mille põhjuseks oli industrialiseerimine. Viimastel aastakümnetel on linnastumine jätkunud, mille tulemusena on aina rohkem rohealad asendunud hoonetega ja neid teenindatavate teedega ning platsidega, mis on kõvakattega (asfalt või kivisillutis). See kõik on tinginud olukorra, kus enamus Eesti linnades välja ehitatud sademeveesüsteeme on suure tõenäosusega aladimensioneeritud. Selle tulemusena on sagenemas uputused Eesti linnade sademeveesüsteemides, kus sademeveesüsteem ei suuda vastu võtta kogu sademeveevett. Eestis saab esile tõsta Tartus ja Tallinnas aastatel 2016 ja 2017 aset leidnud valingvihmasid, mis põhjustasid varalist kahju. 03.07.2016 hoovihm põhjustas Tallinnas mitmel pool suuri üleujutusi, kui ühe tunniga sadas maha 40 mm. Samal 5 päeva Tartus oli lühialaine uputus Lõunakeskuse parklates (Joonis I), ametlikult mõõdeti sademetehulgaks 25 minutiga 21 mm. Järgmisel aastal 17. augustil põhjustas tugev vihmasadu Rocca al Mare keskuses ja parklas uputuse, mis sai ka suure vastukaja meedias. Selliseid näiteid leiab palju, sh 2020.a. Antud uuringus käsitletakse kliimamuutuse ühte komponenti – lühiajalisi sademeid. Sademeveesüsteemid projekteeritakse enamasti elueaga 30–50 aastat. Seega on lisaks kaasajastatud arvutusvihmadele vajalik teada ka võimaliku kliimamuutuste mõju tulevikus. Töös tehakse trendianalüüs kõikidele meteoroloogiajaamadele, analüüsides muutuseid arvutusvihmade intensiivsustes. Analüüsi tulemuste põhjal uuritakse kas ja kuidas võtta arvesse võimalikku kliimamuutuste mõju tulevikus. Projekti põhieesmärgiks on statistiliselt analüüsida mõõdetud lühiajalisi sademeid, mille põhjal pakutakse välja uus arvutusvihmade metoodika sademeveesüsteemide projekteerimiseks. Antud metoodika peab olema rakendatav Eesti territooriumil mis tahes asukohas. Teiseks eesmärgiks on välja selgitada võimaliku kliimamuutuse mõju suurus ja trend Eesti arvutusvihmades ning välja pakkuda lahendus, kuidas projekteerimisel arvestada kliimamuutuse mõju ka tulevikus. Kolmandaks koostatakse võrdlusanalüüs hetkel kehtiva Eesti Vabariigi standardi 848:2013 «Väliskanalisatsioonivõrk» ja töö käigus saadud tulemuste vahel

The intensification of short-duration rainfall extremes due to climate change – Need for a frequent update of intensity–duration–frequency curves

Funding Information: This work was supported by the Estonian Environmental Investment Center project “The revision of urban drainage stormwater system design principles” [grant number T180045MIMV]. We gratefully acknowledge the financial support of the European Regional Development Fund in publishing this paper. The study was also part of the EviBAN project (Evidence based assessment of NWRM for sustainable water management) funded by the EU Water JPI and the Academy of Finland (no 326787). Publisher Copyright: © 2023 The AuthorsNumerous studies have investigated future changes in extreme precipitation by employing climate models. However, trends in extreme short-duration (20–180 min) rainfall intensities, that is, design storm rainfall intensities used for stormwater infrastructure design, have received considerably less attention despite their importance. This study quantified the effect of climate change on design storm intensity based on observations. Trends were investigated for diverse short-term rainfall durations, ranging from 20 to 180 min, at 11 meteorological stations in Northern Europe, Estonia. The Mann-Kendall test and Sen's slope estimator were used to detect trends and calculate the trend magnitudes by analyzing a 70 year period of high-resolution temporal observed rainfall data. The Sen's slope indicated a positive magnitude of slopes for all the durations and stations investigated, and two stations in Northeast Estonia showed significantly increasing trends (p < 0.05). Unsurprisingly, the spatial distribution of trends revealed notable variations from station to station, as extreme rainfall events are heavily localized due to cloudburst. Despite this variety, it can be generalized that the annual maximum rainfall intensities in Estonia have increased at an average rate of 4 % per decade due to changing climate conditions, invariant of the rainfall duration analyzed. The use of decades enables to easily keep the intensity–duration–frequency curves updated, and it is more practical and relatable for engineers as well. The findings of this study provide critical knowledge for urban water management decision-makers, indicating the need to frequently update urban design criteria to design climate resilient urban infrastructure.Peer reviewe

Climate change adaptation using low impact development for stormwater management in a Nordic catchment

Climate change is raising a need to adapt stormwater management systems to altered conditions. Low Impact Development (LID) controls are regarded as a promising solution for adaptation in urban areas. The main objective was to demonstrate how LID controls function in climate change adaptation. The analysis used air temperature and precipitation from regional climate model with RCP8.5 emission scenario as input to the Storm Water Management Model. Urban runoff and snow dynamics were simulated in historical, mid- and far-future periods. With the increase in mean air temperature, snow water equivalent reduces, which alters the seasonal runoff behavior in the future. To alleviate the climate change impacts, subcatchments generating high total runoff volumes were determined for LID implementation. Bioretention cells, permeable pavements and green roofs achieved runoff volume reduction in summer, while also having some impact on other seasons. Permeable pavements and bioretention cells behaved similarly throughout the year, but green roofs had a negligible runoff volume reduction in winter. This study highlights that LID adaptation design for summer flow events does not behave similarly in other seasons

Climate change adaptation using low impact development for stormwater management in a Nordic catchment

Climate change is raising a need to adapt stormwater management systems to altered conditions. Low Impact Development (LID) controls are regarded as a promising solution for adaptation in urban areas. The main objective was to demonstrate how LID controls function in climate change adaptation. The analysis used air temperature and precipitation from regional climate model with RCP8.5 emission scenario as input to the Storm Water Management Model. Urban runoff and snow dynamics were simulated in historical, mid- and far-future periods. With the increase in mean air temperature, snow water equivalent reduces, which alters the seasonal runoff behavior in the future. To alleviate the climate change impacts, subcatchments generating high total runoff volumes were determined for LID implementation. Bioretention cells, permeable pavements and green roofs achieved runoff volume reduction in summer, while also having some impact on other seasons. Permeable pavements and bioretention cells behaved similarly throughout the year, but green roofs had a negligible runoff volume reduction in winter. This study highlights that LID adaptation design for summer flow events does not behave similarly in other seasons

Modelling urban stormwater management changes using SWMM and convection-permitting climate simulations in cold areas

Funding Information: This work was supported by the EviBAN project (Evidence based assessment of NWRM for sustainable water management), which is under the EU Water JPI WaterWorks2017 ERA-NET Cofund and funded in Finland by the Academy of Finland (no 326787). The HCLIM simulations were performed by the NorCP (Nordic Convection Permitting Climate Projections) project group, a collaboration between the Danish Meteorological Institute (DMI), Finnish Meteorological Institute (FMI), Norwegian meteorological institute (MET Norway), and the Swedish Meteorological and Hydrological Institute (SMHI). Publisher Copyright: © 2023 The AuthorsUrbanization coupled with climate change is expected to put pressure on the urban stormwater network. To predict and mitigate the effects of these trends, accurate modeling of urban stormwater changes is required at scales and resolutions meaningful to stormwater management. Although numerous studies have analyzed the effect of climate change on urban flooding risk using the event-based approach, none have incorporated the continuous modelling approach to investigate the whole spectrum of changes in an urban catchment. This study analyzes seasonal changes in future urban hydrological behavior using a mini-ensemble of six state-of-the-art climate model projections and a calibrated hydrological-hydraulic Storm Water Management Model (SWMM). The modelling results show future changes in seasonal and monthly hydrological behavior. The notable winter warming is the major driver in the future snow processes, resulting in considerably less snow days and an increase in the flow events frequency during the winter months. The modelling results also suggest an increase in the annual maximum hourly flow in all seasons, with the clearest trend modelled in winter. Monthly average runoff during the cold period is modelled to increase, while no clear trends are detected for the rest of the year. There is a clear added benefit in using convection-permitting regional climate models throughout the year. Overall, the climate change mitigation and adaption strategies in urban catchments should focus more on the whole spectrum of changes rather than only on urban pluvial flooding risk. These findings call for a transition from traditional to a more advanced stormwater management.Peer reviewe

Processes influencing stormwater purification by roadside biochar-amended sand filter in cold climate conditions

Stormwater in Finland typically lacks substantial treatment despite potentially containing elevated concentrations of nutrients and trace metals that can degrade the water quality of receiving waterbodies. Reactive materials, such as biochar, have been effective in removing pollutants from stormwater. However, knowledge of their performance is primarily based upon laboratory tests as field studies remain scarce and there is little evidence on their long-term field performance. This study evaluated field-scale stormwater pollutant retention by sand and biochar-amended sand filtration systems designed to treat road runoff containing metals and nutrients in southern Finland. Results of field data, and hydrological and geochemical modelling suggest that the filters retain pollutants similarly through a combination of physical filtration, (ad)sorption and/or (co)precipitation additionally affected by leaching of alkali metal cations from biochar media which contributed to the formation of new minerals via PO43- sorption to Fe (oxy)hydroxides or precipitation of Ca phosphate mineral phases (hydroxyapatite)

Processes influencing stormwater purification by roadside biochar-amended sand filter in cold climate conditions

Stormwater in Finland typically lacks substantial treatment despite potentially containing elevated concentrations of nutrients and trace metals that can degrade the water quality of receiving waterbodies. Reactive materials, such as biochar, have been effective in removing pollutants from stormwater. However, knowledge of their performance is primarily based upon laboratory tests as field studies remain scarce and there is little evidence on their long-term field performance. This study evaluated field-scale stormwater pollutant retention by sand and biochar-amended sand filtration systems designed to treat road runoff containing metals and nutrients in southern Finland. Results of field data, and hydrological and geochemical modelling suggest that the filters retain pollutants similarly through a combination of physical filtration, (ad)sorption and/or (co)precipitation additionally affected by leaching of alkali metal cations from biochar media which contributed to the formation of new minerals via PO43- sorption to Fe (oxy)hydroxides or precipitation of Ca phosphate mineral phases (hydroxyapatite)