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Viru-Peipsi veemajanduskava - Keskkonnaministeerium

Viru-Peipsi veemajanduskava - Keskkonnaministeerium

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3.1.2 Lämmijärv ja Pihkva järv<br />

37<br />

3.1.2 Lake Lämmijärv and Lake Pihkva<br />

kordistunud. Põhjuseks saab olla järve fosforikoormuse<br />

järsk suurenemine (mille kohta puuduvad<br />

andmed) või põhjasetete mõju veekvaliteedile.<br />

Tõenäoliselt on tegemist mõlemaga, sest<br />

koormuse väikesest tõusust ja vetikate arenguks<br />

soodsatest ilmastikutingimustest tingitud vetikaõitsengud<br />

põhjustavad omakorda fosfori vabanemist<br />

setetest vette ehk järve nn enesereostust.<br />

Erinevate rahvusvaheliste projektide ühine<br />

eksperthinnang <strong>Peipsi</strong> järve seisundile on järgmine:<br />

<strong>Peipsi</strong> Suurjärv on „rahuldavas“ seisundis,<br />

Lämmijärve ja Pihkva järve seisund varieerub<br />

„rahuldava“ ja „halva“ vahel. Eutrofeerumise<br />

peatamiseks on kõige tõhusam vähendada<br />

fosfori sissekannet järve.<br />

Lämmijärv and in the opposite direction in the<br />

western part. Also the River Võhandu, which<br />

flows into the southern part of the lake, has a<br />

certain impact on the water quality of Lämmijärv.<br />

Figures 3.2 and 3.3 show considerable differences<br />

between the status of Lake <strong>Peipsi</strong>, Lake Pihkva<br />

and Lake Lämmijärv. While the status of <strong>Peipsi</strong><br />

has stabilised in the last decade in terms of both,<br />

phosphorus and nitrogen, the phosphorus concentration<br />

in Lake Pihkva has increased nearly<br />

threefold in the same period. This can be caused<br />

by a sharp increase in phosphorus load (on which<br />

there are no data) or the impact of bottom sediments<br />

on water quality. It is likely that both reasons<br />

have been involved because algal blooms<br />

caused by a small increase in load and by<br />

favourable weather conditions lead to the release<br />

of phosphorus from bottom sediments, i.e. the<br />

so-called self-pollution of the lake.<br />

Different international projects have formulated<br />

the following joint expert judgement on<br />

the ecological status of Lake <strong>Peipsi</strong>: Lake<br />

<strong>Peipsi</strong> Suurjärv is in a moderate status, the<br />

status of Lake Lämmijärv and Lake Pihkva varies<br />

between moderate and poor. The most effective<br />

way of stopping eutrophication would<br />

be to decrease the inflow of phosphorus into<br />

the lake.<br />

Joonis 3.3. Üldlämmastiku sisalduse dünaamika <strong>Peipsi</strong>s, Lämmijärves ja Pihkva järves (mgN/m 3 , geomeetriline keskmine)<br />

Allikas: Külli Kanguri ettekanne <strong>Peipsi</strong> seisundi hindamise seminaril 22.01.2004 (Environmental status of Lake <strong>Peipsi</strong> based on the existing<br />

data and results of joint expeditions. Külli Kangur, Tõnu Möls, Andu Kangur, Peeter Kangur, Reet Laugaste, Anu Milius, Helle Mäemets)<br />

Figure 3.3. Dynamics of total nitrogen in Lake <strong>Peipsi</strong>, Lake Lämmijärv and Lake Pihkva (mgN/m 3 , geometric average)<br />

Source: Presentation of Külli Kangur on a seminar “Environmental status of Lake <strong>Peipsi</strong> based on the existing data and results of joint<br />

expeditions”, 22.01.2004. Külli Kangur, Tõnu Möls, Andu Kangur, Peeter Kangur, Reet Laugaste, Anu Milius, Helle Mäemets

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