Recharge systems for protecting and enhancing groundwate

TOPIC 6
Region issues and artificial recharge case studies / Case studies 757
measured from the compiled piezometric maps (Stavropoulos, 1992, Voudouris, 1995). The mean hydraulic conductivity
was estimated to be 1.5 x 10 –5 m/s and the S-coefficient in Plio-Quaternary deposits about 1.5 x 10 –4 .
FIELD EXPERIMENTS
Six (6) new boreholes were drilled (Fig. 1): three in Larisos basin (B1, B2, B3), and three in Piros basin (B4, B5 and
B6). The selection of the location was done by using criteria like availability of land, high permeability, gravity flow
from water source to recharge borehole, etc. After each borehole had been drilled, pumping tests were carried out,
in order to estimate the critical yield (Table 1).
Table 1. Drilling data of recharge boreholes.
Borehole
Geological
formation
Depth
(m)
Critical yield
(m3/h)
Groundwater level
(m b.g.s.)
B1
B2
Sandstones and conglomerates
(flysch deposits)
Sandstones and conglomerates
(flysch deposits)
242 75
241 35
B3 Sands, gravels, conglomerates 215 100
B4 Sands, gravels, conglomerates 196 100
B5
Sandstones and conglomerates
(flysch deposits)
202 25
B6 Limestones 180 30
51.08
(1/3/02)
23.46
(10/4/02)
9.61
(4/4/02)
22.61
(8/4/02)
23.08
(6/3/02)
6.21
(18/4/02)
Water from surface runoff and springs, without any treatment, was used during the aquifer recharge experiments in
the boreholes, (Table 2). The water was transferred at each site via the existing irrigation network. Measurements of
groundwater level were made in the piezometers of the recharge boreholes, as well as in the neighbouring observation
boreholes.
Table 2. Results of the conducted groundwater recharge tests
Borehole
Recharge water
Period /Duration
(days)
Recharge
flow rate
(m3/h)
Water
volume
(m 3 )
Water
level rise
(m)
B1
Surface water
1/3/2002–2/5/2002
63 days
42 63,500 44.93
B2
Surface water
10/4/2002–30/4/2002
20 days
13 6,200 19.83
B3
Discharge of springs
4/4/2002–4/5/2002
30 days
10 7,200 4.16
B4
Irrigation canal
8/4/2002–3/5/2002
26 days
75 46,800 8.51
B5
Surface water
6/3/2002–6/4/2002
32 days
12 9,200 13.61
B6
Discharge of springs
18/4/2002–5/5/2002
18 days
8 3,500 3.26
10 – 16 June 2005, Berlin ■ 5th International Symposium ■ AQUIFER RECHARGE ■ ISMAR 2005