Viru-Peipsi veemajanduskava - Keskkonnaministeerium

4.1 Põhjaveekogumite üldiseloomustus
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4.1 General description of groundwater bodies
ˆ
(D 1
rz) and Tilze (D 1
tl) of groundwater. Bigger higher NH 4
concentration is
horizons. When consumed central water intakes probably due to anaerobic
together with lower located in Põlva, Elva environment of the water body.
Silurian aquifers, the and Tartu. Appr 10–20%
groundwater body of the stock in use.
is regarded as the Only in Tartu the
Middle Devonian-Silurian groundwater regime is
water complex; 2–6 significantly influenced
by water abstraction
(abrupt changes in
water tables).
Ordovician Ida-Viru The 30 m thick upper Source of water supply High NH 4
content, low pH and
groundwater body part consists of for the sparse population high permanganate consumption
(2043) limestones and dolomites, of Ida-Viru County, value are probably due to
strongly karsted and especially its southern natural factors (extensive mire
fissured at places; part. Appr. 10% of the complexes), i.e. not pollution.
in the up to 20 m stock in use.
thick upper part –
5–30, in the depth of
20–50 m – 3–5 and
in depths over
50 m – 1–2.
Ordovician groundwater Unusable as a source of Chemical status poor. In nearly
body of the Ida-Viru oil water supply (polluted), 20% of the studied bore wells
shale basin endangers the water of or test wells, the concentration
(1154) other groundwater bodies. of SO 4
exceeds 250 mg/l and
50–90% of the stock is also the concentration of
being pumped out in benzopyrene exceeds the
connection with oil shale standard for drinking water.
mining. After the closure Drainage works have increased
of oil shale mines, the the mineral content of groundgroundwater
body may water 2–3 times and also the
have an impact on other hardness of water has increased,
water intakes; rising of currently reaching 10–16 mg-eq/l,
water table will cause which limits the possibilities of
paludification.
industrial use of the water (water
needs prior processing).
Silurian-Ordovician Limestones and Used in sparsely Groundwater confined, not
groundwater body beneath dolomites; 1–10. populated areas and vulnerable to pollution. Chemical
Devonian layers Together with the in the towns of Tartu, status good, meets drinking
(4408) Pärnu aquifer, the Elva and Põlva. water standards. The excessive
water body forms 10–20% of the stock NH 4
concentration occurring at
the Middle Devonian- in use. places is caused by anaerobic
Silurian water
environment of the
complex at places.
groundwater body.
Silurian-Ordovician Strongly karsted The Viru and Peipsi parts Many wells with high NO 3
and
aggregated groundwater and fissured limestones of the groundwater body NH 4
content in the Peipsi part
body (5859) and dolomites; are important due to their (eastern edge of the Põltsamaa-
Peipsi part (4121) in the upper, up to abundance in water; they Adavere nitrate sensitive area),
Viru part (1738) 20 m thick part – are used in thousands of Also oxygenation is high in
5–30, in the depth wells in sparsely populated many wells (permanganate
of 20–50 m – 3–5 areas. Bigger central water oxygenation >5), probably due
and deeper than intakes in Tamsalu, Rakvere, to higher content of organic
50 m – 1–2. Kadrina, Toolse, Jõgeva and substances in karst water and