Viru-Peipsi veemajanduskava - Keskkonnaministeerium

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4.4 Põhjavee seisundi hinnang 4.4 Status of groundwater bodies
linn on eestkätt metsaalal paiknev suvituspiirkond,
pole linnastu mõju siiani täheldatud. Hea põhjaveeseisundi
säilitamiseks tuleks võimaluste korral
põhjaveekogumi piires vältida potentsiaalselt ohtlike
reostuskollete lisandumist.
Põllumajandus
Põhjavett mõjutavatest põllumajandustegevustest
on üheks probleemsemaks väetiste ja taimekaitsevahendite
kasutamine ehk hajureostus, mida
on suhteliselt raske kontrollida. Väetiste ja pestitsiidide
kasutamise mõju avaldub eestkätt kõige
ülemises põhjaveekogumis (sügavusel 10–30 m)
ning reostusele viitab tavaliselt kõrgenenud nitraatide
sisaldus. Nitraatide sisalduse looduslik
foon põhjavees on 0–5 mg/l. Olmereostus suurendab
nitraatide sisaldust kaitsmata aladel 7–15
mg/l-ni. Aiamaadega tiheasustusaladel võib nitraatide
sisaldus olla 2–3 korda kõrgem. Suurem
nitraatide sisaldus viitab juba põllumajanduse
mõjule – 10 kg/ha saagis kasutamata jäänud läm-
Elva groundwater body, 50% of which falls within
the territory of Elva Town or some other settlement.
As the town of Elva is a summer resort located
in a forested area, no influence of the urban
area has been observed to date. To preserve
the good status of groundwater, generation of
new potentially dangerous pollution hot spots
should be avoided within the boundaries of the
groundwater body.
Agriculture
Among agricultural activities affecting groundwater,
the severest problems are connected with the
use of fertilisers and pesticides (non-point pollution),
which is relatively difficult to control. The
impact of the use of fertilisers and pesticides is
expressed primarily in the upper groundwater
body (at the depth of 10–30 m) and pollution
can usually be detected by an increased nitrate
content. The natural background concentration
of nitrates in groundwater is 0–5 mg/l. Domestic
pollution increases the nitrate concentration in
areas with vulnerable groundwater to 7–15 mg/l.
Table 4.3. Land use in the outcrop areas of upper groundwater bodies
Name of groundwater body Natural Arable Settlements Industry
Ordovician-Cambrian groundwater body
(land use in the 150 km 2 outcrop area presented here*) 74% 16% 8% 2%
Ordovician Ida-Viru groundwater body
(first aquifer 1964 km 2 ; Q excluded) 85% 12% 2% 1%
Ordovician groundwater body of Ida-Viru oil shale basin 70% 17% 5% 8%
Silurian-Ordovician aggregated groundwater body,
Peipsi part (first aquifer 4009 km 2 ; Q excluded) 71% 26% 2% 1%
Silurian-Ordovicianaggregated groundwater body, Viru part 59% 37% 3% 1%
Upper Devonian groundwater body 68% 29% 2% 1%
Middle Devonian groundwater body
(first aquifer 5990 km 2 ; Q and D3 excluded) 65% 31% 3% 1%
Middle Lower Devonian groundwater body
(first aquifer 1388 km 2 ; Q and D2 excluded) 79% 17% 1% 3%
Vasavere groundwater body 80 km 2 83% 5% 1% 11%
Meltsiveski groundwater body 8.7 km 2 9% 4% 65% 22%
Quaternarian aggregated groundwater body 325.2 km 2
incl. Sadala 55.6 km 2 20% 74% 6% 0%
incl. Laiuse 56.1 km 2 24% 70% 5% 1%
incl. Saadjärve 80.7 km 2 31% 62% 6% 1%
incl. Elva 7.4 km 2 39% 11% 50% 0%
incl. Piigaste-Kanepi 39.6 km 2 63% 34% 3% 0%
incl. Võru 76.1 km 2 70% 17% 13% 0%
* On the outcrop area of the groundwater body, groundwater runoff is currently taking place. This would be of importance only in case the
water table of the groundwater body would be so low that precipitation water could infiltrate into the groundwater body.