Rannikujärvede tervendamine
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Kuupäev
2025
Kättesaadav alates
05.09.2025
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Rannikujärved on ainulaadsed üleminekuökosüsteemid mere ja maismaa vahel, mille arvukus Eestis maatõusu tõttu pidevalt kasvab. Need veekogud on sageli halvas ökoloogilises seisundis inimtekkelise reostuskoormuse ja Läänemere seisundi muutuste tõttu, mistõttu on nende tervendamine Veepoliitika Raamdirektiivi eesmärkide saavutamiseks oluline, ent nende eripärade tõttu tavapärastest siseveekogudest keerukam. Käesoleva töö eesmärk on analüüsida rannikujärvede tervendamise võimalusi ja selgitada välja nende spetsiifilistele tingimustele, sealhulgas muutuvale soolsusele ja veetasemele, sobivaimad meetodid. Töös kasutati kirjandusallikate süstemaatilist analüüsi ja erinevate tervendusmeetodite võrdlevat hindamist, arvestades rannikujärvede ökoloogilisi eripärasid.
Uurimistöö tulemused näitavad, et rannikujärvede edukaks tervendamiseks on vajalik terviklik ja prioritiseeritud lähenemine. Esmatähtsad on valglapõhised meetmed, nagu näiteks soostunud alade veerežiimi taastamine ja kuivenduskraavide sulgemine, mis võivad vähendada toitainekoormust (N, P) järve kuni kolmandiku võrra. Järvede hüdroloogilise tasakaalu taastamine, sealhulgas veetaseme püsiv tõstmine 0,3–0,5 meetri võrra, parandab vee kvaliteeti ja valgusolusid ning toetab elustiku mitmekesisuse suurenemist. Lokaalsed meetmed, nagu setete eemaldamine, annavad küll kiireid tulemusi vee läbipaistvuse paranemisel, kuid on kõrge maksumusega ja pigem sobivad väiksematele, tugeva inimmõjuga järvedele. Oluliseks osutus ka sidusrühmade varajane kaasamine, mis lühendas planeerimisprotsessi keskmiselt 18 kuu võrra ja vähendas konflikte. Töö tulemused pakuvad praktilist raamistikku rannikujärvede tervendamismeetmete valikuks ja rõhutavad vajadust käsitleda neid eraldiseisva järvetüübina, mis eeldab paindlikku majandamist ja pidevat seiret.
Coastal lakes are unique transitional ecosystems between sea and land, whose numbers in Estonia are constantly increasing due to land uplift. These water bodies are often in poor ecological condition due to anthropogenic pollution loads and changes in the Baltic Sea status, making their restoration important for achieving the goals of the Water Framework Directive, yet more complex than conventional inland water bodies due to their specific characteristics. The aim of this thesis is to analyze the restoration possibilities of coastal lakes and identify the most suitable methods for their specific conditions, including changing salinity and water levels. The study employed systematic analysis of literature sources and comparative assessment of different restoration methods, considering the ecological characteristics of coastal lakes. The research results show that successful restoration of coastal lakes requires a comprehensive and prioritized approach. Watershed-based measures are of primary importance, such as restoring the water regime of paludified areas and closing drainage ditches, which can reduce nutrient loads (N, P) to the lake by up to one-third. Restoration of lakes' hydrological balance, including permanent water level increase by 0.3–0.5 meters, improves water quality and light conditions while supporting increased biodiversity. Local measures, such as sediment removal, provide rapid results in improving water transparency but are high-cost and more suitable for smaller lakes with strong human impact. Early stakeholder engagement proved crucial, shortening the planning process by an average of 18 months and reducing conflicts. The results provide a practical framework for selecting coastal lake restoration measures and emphasize the need to treat them as a distinct lake type requiring flexible management and continuous monitoring.
Coastal lakes are unique transitional ecosystems between sea and land, whose numbers in Estonia are constantly increasing due to land uplift. These water bodies are often in poor ecological condition due to anthropogenic pollution loads and changes in the Baltic Sea status, making their restoration important for achieving the goals of the Water Framework Directive, yet more complex than conventional inland water bodies due to their specific characteristics. The aim of this thesis is to analyze the restoration possibilities of coastal lakes and identify the most suitable methods for their specific conditions, including changing salinity and water levels. The study employed systematic analysis of literature sources and comparative assessment of different restoration methods, considering the ecological characteristics of coastal lakes. The research results show that successful restoration of coastal lakes requires a comprehensive and prioritized approach. Watershed-based measures are of primary importance, such as restoring the water regime of paludified areas and closing drainage ditches, which can reduce nutrient loads (N, P) to the lake by up to one-third. Restoration of lakes' hydrological balance, including permanent water level increase by 0.3–0.5 meters, improves water quality and light conditions while supporting increased biodiversity. Local measures, such as sediment removal, provide rapid results in improving water transparency but are high-cost and more suitable for smaller lakes with strong human impact. Early stakeholder engagement proved crucial, shortening the planning process by an average of 18 months and reducing conflicts. The results provide a practical framework for selecting coastal lake restoration measures and emphasize the need to treat them as a distinct lake type requiring flexible management and continuous monitoring.
Kirjeldus
Bakalaureusetöö
Kalanduse ja rakendusökoloogia õppekaval
Märksõnad
bakalaureusetööd, eutrofeerumine, valglapõhised meetmed, veetaseme reguleerimine, setete eemaldamine, Läänemeri