PERMFILE102368

• Permit No: M1999002
• IBM Index Class Name: Permit File
• Doc Date: 6/18/1999
• Doc Name: OBJECTORS EXHIBITS
• Media Type: D
• Archive: No

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III I II I II I II IIII III ~ Cases and solutions
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The role of hydrogeology in
solution-subsidence development
and its environmental impa~t~s; a
case-study for Sazlica (Nigde,
Turkey)
M. (elik ~ M. Af}in
Abstract Solution-subsidence and other types of
:ollapse failures developed in the vicinity of Sazltca
have been a major source of environmental prob-
lems such as groundwater pollution, soil erosion,
and foundation failures. Extensive pumping of wa-
ter from the Lake Dipsiz during irrigation seasons
creates landslide developments at the shores of the
lake. Five stages of landslide development were ob-
served in the unconsolidated soils around Lake
Dipsiz. Bowl-shaped solution-subsidence features
with depths from 1 to ~ m and diameters betveen 1
and 60 m were formed due to excess pumping, and
recharge and discharge features of unconfined
aquifer. The pumping activities must he controlled
to prevent further environmental problems. Lake
Dipsiz and other subsidence developments are the
groundwater exposure areas highly vulnerable to
contamination. The proposed remedies for over-
coming the environmental problems are the estab-
lishment of conservation areas around such natural
features; ceasing the removal of top soil, controlling
the urbanization, and keeping the livestock farming
away from the areas susceptible to pollution.
Key words Lake Dipsiz ~ Solution-subsidence
Landslide ~ Groundwater pollution ~ Excessive
pumping
Received: 2 June 1991 ~ Accepted: 16 January 1996
M. (elik (®)
Ankara University, Geological Engineering Cept.,
TR-06100 Tondo§an, Ankara, Turkey
Fax: [phone] ~ e mail celikmascience.ankara.edutr
M. Afyin
Nigde University, Geological Engineering Dept.,
TR~68100 Aksaray, Turkey
Introduction
The studv area is located in the Sazllca \ illage between
Nigde and Bor and covers an area of about 65 km~ com-
posed of alluvium (Fig. I). Environmental problems
caused by the karstic formations in the area are discussed
within the context of this paper. The detailed topographic
map of an area of 2500 hm' was prepared in the scale of
1/2000 (Fig. 2).
Former geological studies have been carried out by bITA
(1961) and Pasquare (1933), and hydrogeological studies
by Gulenbay (1972). Further studies in different locations
focusing on the karst formations and their effects on the
environment have been performed by i`lilanovic (1981),
Canik and ~orek4ioglu (1935), White and others (1986),
Beck (1936, 1933), Daoxian (19SS), Wilson and Beck
(1992), Ford (1993), Shagour (199-1), and Bodhankar and
Chatterjee (1994).
The purpose of this study is to investigate the formation
mechanism of subsidence structures observed in buried
karstic areas and the effects of changing hydrogeologic
conditions.
Geological setting
The study area is located in the western part of the Nigde
massif (Gulenbay 1972). The basement units of the massif
are Paleozoic in age and composed of marble, amphybo-
lite, quartzite, gneiss, and schist (Fig. 1).
From Tertiary to Quaternary tuft, tuffite, andesite, ignim-
brite, and agglomerate, the eruption products of Hasan-
dagl volcanism overlie the basement with conglomerates
and lacustrine limestones (Pasquare 1983). All these units
are covered by Quaternary travertine and alluvium. Trav-
ertine occurrence is limited to a small area and alluvium
completes the stratigraphic sequence. Alluvium is inter-
calated with dav, clayey-silty sand, sand}• gravel, con-
glomerate, and clayey sand, and tuff crops out in small
parts.
Environmental Genlnnv 35 13-a1 p,r~„bar IonA ~ ~ Snrir~~• ~r~rl,n ~ 335