New Vision of the Role of Land Reclamation Systems in Nature Protection and Water Management - Wetlands and Water Framework Directive: Protection, Management and Climate Change - page 92

Fig. 6.1 A sketch of the 9.2 km 2 catchment with the network of ditches functioning there
(Kowalewski 2003 ); 1 Grasslands; 2 Arable land; 3 Forests; 4 Grid computing nodes

Table 6.3 Simulation of the retention effects at closed out fl ow from reclamation ditches in the

catchment shown in Fig. 6.1 (Kowalewski 2003 )
Simulated action

Hydrological
effects

Increment
of retention

Variant
I

A lack of water lifting in the reclama-
tion network

Ground water depth in
summer

-

— free out fl ow of water — ca. 100 cm

Variant
II

Closed outflow from the reclamation
network since April 1

Ground water depth in
summer — 0cm

ca.
386,000 m 3

ow from ditches since April 1 results in the ground water
level close to land surface, so it should not be applied in croplands. Such a variant
may be considered only for lands abandoned by agriculture.

Completely closed out fl

6.4 Ecosystems that Might Be Signi cantly Affected

by Land Reclamation

Water-related ecosystems constitute 14 % of the Poland s area; most of them are

agricultural grounds used as meadows and pastures. There are 135 plant commu-
nities in grasslands out of 360 noted in Poland. From among 76 Polish natural
habitats environmentally important

'

for Europe and protected by the Habitat

Directive (Dyrektywa 92/43/EWG … ), 28 are associated with agricultural areas and