Sustainable development and regulation of karst aquifers
Dr Zoran Stevanovic, Prof. University of Belgrade, Serbia FMG, Department of Hydrogeology [email protected]
“Linking waste water management to ICZM and IWRM with emphasis on karstic coastal areas" Split, Croatia, 19-22 March 2012. Topics
Importance of karst aquifers and their utilization in SEE Groundwater balance and resources assessment in karst Storativity as the main factor in regulation of karst aquifers Sustainable use and regulation of karst waters 1. Importance of karst aquifers and their utilization in SEE
Karst phenomena and their distribution
Margat et al. Alpine orogenesis geostructures
The geology of the region is complex. For most of the Mesozoic period, the Thetis Ocean covered this area, whereas during Tertiary its central part was exposed to the Alpine orogenesis when the majority of today’s mountains were uplifted and folded. The homeland of “classical karst”. Mesozoic carbonates are spread out in the central part of the region arch and its terminal parts: In the western and southern adjacent areas – Apennines, Alpides, Dinardes, Pindes and Hellenides as well as Carpathian – Balkan region. Along with alluvial groundwater and surface water from the reservoirs, the water from the karstic springs is the main source of water supply in the region. Tapping large springs is the traditional method of water supply in the region but the main concern is their unstable discharge regime. SEE Europe
• In the Alpine orogenic belt the karstified carbonate rocks are either dominant, as in the Dinarides, or widely distributed, as in the Carpathian-Balkans, Hellenides or Pindes. • Concerning karstic groundwater resources, this region is by far the richest in all of Europe. • Some areas, such as southern Montenegro where the average specific yield is over 40 l/s/km2, are characterized by a very intensive water balance. • In several countries in the region water supply from karstic aquifers prevails.
Karst in Turkey
Courtesy of G.Gunay There are several large cities in SEE with populations of over a half of million that depend on karst aquifers and their discharge regimes. Among them are the five capitals Vienna, Tirana, Skopje, Sarajevo, and Podgorica, whereas some other big cities such as Banska Bystrica, Niš, Craiova, Constanza, Thessaloniki use either only karstic waters or, in case of insufficient discharge, combine them with water from other sources. Main advantage and disadvantage of tapping karst aquifers
(+) The exploration of karst groundwater is more costly and less predictable in terms of final outcomes, but the extraction is regularly much cheaper and environmentally friendly than surface water use. (-) Due to the unstable regime of the karstic sources, the main problem for most of the waterworks is to ensure water supply during recession periods. Tapping karstic springs - Traditional way of water supply since Roman time
An ancient art in the area. We all learn from Roman time experiences
11 long aqueducts delivered more than 13 m3/s of water to Rome from distances ranging from 16-91 km.
Several water supply systems from that time are completely reconstructed but still use the same springs and pipeline routes. Vienna water supply
Water supply system is more than 130 years old. It consists of two major gravity pipelines 150 and 180 km long, and one reserve system of Ranney wells (shaft with horizontal drains) in alluvium. First Viennese mountain spring pipeline is tapping water from Schneeberg, Rax and Schneealpe mountains and second pipeline from Hochschwab Mt. The total catchment is around 600 km2. The long concrete tunnels and channels provides daily 400.000 m3 or 4,6 m3/s in average, for some 1,5 million of inhabitants.
Total length of public pipelines: 3,263 km Total number of house mains: 100,832 Maximum daily consumption (June 12, 2003): 531,970 m3 Kaiserbrunn spring (Rax Mt, Vienna), the masterpiece of design and intake quality from the 19th Ct Sarajevo and Podgorica water supply
Vrelo Bosne springs. The discharge of this group of springs that drain rich Triassic aquifer of the Igman Mt. is in the range of 1.4 – 24 m3/s Skadar basin is one of European’s largest GW reservoirs Mareza source:
Q = 2 - 10 m3/s;
Ascending springs at the contact of limestones and fluvial - glacial sediments
At 25 m a.s.l.
Only chlorination applied Tirana water supply
Albanian capital Tirana gets its water in part from the source that drains karstic aquifer at a nearby Mali me Gropa highly karstified plateau (Upper Triassic - Lower Jurassic in age). The karst springs Selita (Q = 0.24 – 0.86 m3/s) and Shemria (Q = 0.45 – 1.50 m3/s) are in
Selita use since Mid of XX Ct., while Spring the third spring Buvilla issues from the Upper Cretaceous dolomite formation of Dajti Mountain massif (and flow into downstream constructed reservoir). Groundwater is low mineralized and of good quality. Natural conditions and unpopulated catchments are in favor of Courtesy of R.Eftimi sanitary protection. Skopje water supply
The capital Skopje gets most of its drinking water from karstic aquifer. Rasce spring is situated on the Vardar River bank upstream of the town. The spring appears from the Zeden massif consists of the marbles, but the tracing tests and isotopic analyses confirmed that only 30% of the water comes from those rocks. The majority of Rasce water is from porous aquifer that exists in the upper-positioned Polosko polje and from the percolated Vardar water lost in the upstream river sections. The discharge regime is relatively stable; the mean flow is 2.5 m3/s. Dumanli spring / Turkey
The enormous Dumanlı spring in the Mediterranean region of Turkey already submerged by the year 1982 by about 120 m head produced by the Oymapınar Reservoir. The spring contributes one third to the annual discharge of the Manavgat River, that will be dammed at Oymapınar. The mean discharge of the spring is estimated at about 50 m3/s;
Courtesy of G.Gunay Bulgarian karstic aquifers
In Paleozoic marbles; in Triassic carbonate complex;
In Upper Miocene limestones. Ex. Iskrets spring: 35 km from Sofia, Q=0.1-15 m3/s. Extreme max 56 m3/s
16000
14000 12000 10000
8000 6000
Discharge,l/s 4000 2000 0 1963-1997 year Romanian karstic aquifers
1.Carpathian Orogen karst type, 2. the North Dobrogea karst type, 3. the Platform karst type and the 4. Carpathians post-tectonic cover karst type (by Oraseanu) Despite non-extensive outcrops of the karst in comparison with the large territory (some 4%), the karstic aquifers are richest in water and most prospective Water supply of Constanza, Craiova… The largest springs: Izvarna (Q Min / Max = 1.0 / 2.5 m3/s, tapped for 115 km far Craiova); Cerna (F = 85km2; Q Min / Max = 0.5 / 10 m3/s)
Courtesy of A.Iurkiewicz Serbian karstic aquifers
Dinaric and Carpathian’s karst sources provide about 35% of the drinking water to the population in western and eastern part of the country.
The largest springs: Mlava (Q Min / Max = 0.3 / 14 m3/s); Perucac (Q Min / Max = 1.3 / 6.2 m3/s) Karstic sources and water shortage problems along the coast
Adriatic and Ionian coastal tourist areas strongly depend on groundwater from the karst. There, besides the problem of water shortage during the recession period (summer-autumn), water pollution or salty water intrusion often means that local water and economy sectors cannot be expanded and properly developed.
Very important springs supplying Croatian coast such as Jadro (Split), Ombla (Dubrovnik), islands and smaller tourist resorts. Timavo, with an average discharge rate of 30 m3/s, has been tapped to supply water to Trieste.
Rizana near Koper is the main source for supplying water to the Slovene 3 3 coastal zone. Its average discharge is 4.3 m /s (Qmin= 0.03 m /s). The Zvir group of springs were tapped at the end of the 19th century to supply water to Rijeka, the largest Croatian port. The discharge varies between 0.6 and 3.0 m3/s (Biondic and Goatti 1984).
Jadro Spring is the main source for the water supply of Split. The average minimum discharges of Jadro during the recession period are 3– 5 m3/s, while maximum discharges are often over 50 m3/s (Bonacci 1987).
Ombla Spring is the largest permanent karstic spring in the South Adriatic. It supplies the city of Dubrovnik. Qmin = 2.3 m3/s Montenegro coastal springs Q min:max 1:100.000 ?!
Thessaloniki combine system of water supply
The springs Aravissos are drain the karst aquifer of Paiko Mountain (some 50 km West from the city). During the period 1994 – 2007 annual amount of water distributed to the city varied from 27 x 106 m3 – 55 x 106 m3. Due to increased demands (240.000 m3/day) groundwater abstraction from the porous aquifer system of the Thessaloniki - Axios basin is intensified, while since 2003 the water of Aliakmon river also partly supply the city (Spachos et al. 2006) 2. Groundwater balance and resources assessment in karst Balancing GW is not an easy task !
Invisible, even had been declared as “misterious” resource!
“…so secret, occult and concealed that an attempt to administer any set of legal rules in respect to it, would be involved in uncertainity” Supreme Court of Ohio (1861) (courtesy of T. Cincaid)
Litospheric groundwater ~ 23 x 106 km3
Half of them are fresh water, the rest mineralized or hydrothermal dissolutions
In active water cycle ~ 4 x 106 km3
27 Balancing GW quantity (reserves)
Methodologies are variable, depend on aquifer
Aquifers classification based on porosity: 1. Porous (Integranular) 2. Karst (Dissolution) 3. Fissured (Fractured) 4. Complex
Aquifers classification based on HD condition: 1. Phreatic (Unconfined) 2. Artesian (Confined) 3. Complex In karst, major concentration is on discharge rate •Two main types of GW reserves:
1. Natural GW reserves 1.1. Dynamic or replenished reserves 1.2. Static or geological reserves
1.1. + 1.2. = Total reserves (1.1. + 1.2.) – (WDEC + other demands) = Available reserves
2. Artificial GW reserves 2.1. “by coincidence” 2.2. “by purpose” Natural groundwater reserves of karst aquifer – only dynamic (gravity spring case) Natural groundwater reserves of karst aquifer – dynamic & static (case with ascending spring Q1 and underground discharge Q2) 2
I step in balancing : Characterization of karstic aquifer 1 3 Exploitable reserves as part of static reserves: Very bad case
Qexp = n x Qst / T
Qexp = exploitable reserves Qst = static reserves; Qst = x V = av. effective porosity (coeff. karstification) V = volume of saturated zone T = duration of extraction n = exploitation corrective factor
n < 1 !
Over abstraction is ensured Exploitable reserves as total dynamic and part of static reserves: Bad case
Qexp = Qdyn + n x Qst / T
Qdyn = dynamic reserves
If no limitations in water use (WL), over-abstraction is probable Exploitable reserves as total dynamic and part of static reserves but with controlled and limited use: Rare, but logical case
Qexp = Qdyn+ n x Qst / T – WL Temporary use of static waters is justifiable if replenishment potential is suitable !
2 Q()m 3/s Rechargeble potential 1.5
1 Qav
0.5 Qexpl Defic it 0 Time Exploitable reserves as part of dynamic reserves but with controlled and limited usage: Often and safe case
Qexp = Qdyn – WL
WL for eco systems, downstream consumers etc. Often is required 95% flow insuracy “No exploitable reserves” Possible, but not feasible case
Qexp < WL Back to water budget
1 step – characterization
Geometry & Conditions Conditions
Permeability Recharge GW flow direction Drainage Hydrodynamic condition Relationship with surface waters Relationship with other aquifers Regime of GW GW quality Basic budget equation ”balance” Inflow = Outflow +/- Reserves
41 Supportive methods in WR assessment
Stochastic (time series) analysis of spring hydrograph
Method tarisman (recession curve)
Baseflow method and separation of river hydrograph
Method “effective storativity”
Method of discharge regime
Matemathical modeling MONITORING plays key role ! Auto-correlation methods
Courtesy of V.Ristic Recession curve (Mailet, 1905) Baseflow SIMULATION MODEL
Level 1 Supplementation of average monthly discharge series – the MNC module Level 2 Determination of the length of the reference period for assessment of the elements of the multi-annual water balance of the karstic aquifer – the INTKR module Level 3 Assessment of the karst aquifer water balance – the BALANCE module Level 4 - Identification parameters of modulus of transformation functions - TRANSFUNK Level 5 - Simulation of daily discharges - SIMIST Cross-correlogram of daily yields of the Mlava Spring and precipitation levels recorded by 4 rain-gauging/weather stations.
0.14
0.12
0.1
0.08
0.06
0.04
koeficijent korelacije r 0.02
0
0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90 93 96 99 -0.02
-0.04 vremenski korak (dan)
m.s. Crni Vrh m.s. ] uprija m.s. @agubica k.s. Krupaja Courtesy of V.Ristic Towards karst aquifer control
In karst the main problem is water shortage during the recession period (summer- autumn) caused by unstable regime, rapid filtration, reduced rainfall and consequently small discharge 2 of karstic springs. Q()m3/s Rec hargeble potential Control of karst aquifer has 1.5 analogous effects with managing water resource of a surface reservoir. The aim is 1 to take in the necessary water Qav volume during a limited time period by counting on water 0.5 Qexpl replenishment during the next Defic it wet season. Contrary to arid areas where 0 such approach often lead to Tim e aquifer over-exploitation, in SEE region the climatic and hydrogeological preconditions provide an adequate replenishment potential. Over-exploitation? Groundwater mining ?
… refers solely to the depletion of a stock of non-renewable groundwater, so leaving the aquifer dewatered indefinitely. The planned mining of an aquifer is a strategic water resource management option where the full physical, social and economic implications are understood and accounted for over time. A declining water table does not necessarily indicate over-abstraction of the groundwater resource. Over-abstraction should not be defined in terms of an annual balance of recharge and abstraction. Rather, it needs to be evaluated over many years, as the limit between non-renewable stock and the stock that is replenished by contemporary recharge from surface percolation is usually unknown.
Burke & Moench, 2000
…”always full aquifer is equally bad or even worst utilized than one always empty…” Custodio, 1992 Knowledge of the following characteristics of aquifer is of key importance for its regulation:
permeability, discharge regime, position of the groundwater table, position of karstification base (saturated thickness), aquifer’s storativity. AQUIFER CONTROL – needs for adequate storage and replenishment 1. Drill and pump well in the spring vicinity 2. Pump siphons of ascending springs 3. Create underground reservoir 3. Assess storativity in karst
Limited storage = Fast refill and temporary springs – a typical and bad sign!
Q (l/s) P (mm) 10000 0
9000
8000
7000 30
6000
5000
4000 60
3000
2000
1000 90
0 jan.02 feb.02mar.02 apr.02 maj.02 jun.02 jul.02 avg.02 sep.02 okt.02
9000 0
8000 20
7000 40 60 6000 80 5000 P [mm] 100 Q [l/s] 4000 Q-simulated
120 Rainfall(mm) Discharge(L/s) 3000 140 2000 160
1000 180
0 200
7-Jul-02 7-Jul-03
7-Jan-02 7-Jan-03
7-Mar-02 7-Mar-03
7-Sep-02 7-Sep-03
7-Nov-02
7-May-02 7-May-03
Time (Day) Solutions in arid region
Store seasonal flow = Subsurface dams Case example - Gali basera project A “good” storage – chance for successful regulation are raising!
Some of the indicators:
Deeper karstification base; Ascending type spring; Slow drainage during recession (small α); Slow velocity under tracing tests;
Large caverns presence. Although the general methodology of hydrogeological exploration in karst is well described (Milanovic P. 1979; Goldscheider & Drew 2007) there are some specific methods recommended for much more accurate storativity assessment. These two major groups of methods can generally be distinguished as:
Direct Speleology, Cave diving into karst siphons, ROV (remote-controlled vehicle), Camera recording and logging into boreholes, Core drilling and water injection tests. Indirect Stochastic analysis of spring discharge hydrograph, Modeling and 3-D reconstruction of karst physical interior (GIS), Hydrodynamic analysis of pumping test, Tracing test, Geophysical field methods. Diving in submerged springs Fresch water floats on Sea water
Fresch water
Sea water Fresch water
1,50 m Viewpoint for Diver going out External View Bestouan Resurgence
Dye Test Courtesy of L.Potie Port Miou - Marseille sources TDS Before from 3,2 to 18,4 g/l After and Upstream Dam from 1,7 to 5,6 g/l
Courtesy of L.Potie
Camera recording
Courtesy of S.Milanovic Remote controlled vehicle Stochastic modeling and simulating exploitation
6
5
/s)) 3
4
3
2
discharge (karst spring Veliko spring vrelo(karst discharge Q (m 1
0
1-Jan-95 1-Jul-95 1-Jan-96 1-Jul-96 1-Jan-97 1-Jul-97 1-Jan-98 1-Jul-98 1-Mar-951-May-95 1-Sep-951-Nov-95 1-Mar-961-May-96 1-Sep-961-Nov-96 1-Mar-971-May-97 1-Sep-971-Nov-97 1-Mar-981-May-98 1-Sep-981-Nov-98
Qmeasured Qcalculated
Courtesy of V.Ristic Great Loan opportunity ! Good credit – small interest rate !
16 Mlava vauclusian source 14
12
/s) 3
10
8
6 isticanje iz vrela Mlave Q (m isticanje 4
2
0 100
1-Jan-71 1-Jul-71 1-Jan-72 1-Jul-72 1-Jan-73 1-Jul-73 1-Jan-74 1-Jul-74 1-Mar-711-May-71 1-Sep-711-Nov-71 1-Mar-721-May-72 1-Sep-721-Nov-72 1-Mar-731-May-73 1-Sep-731-Nov-73 1-Mar-741-May-74 1-Sep-741-Nov-74
50 Qrealno Qračunsko
0
6 3 )
3 -50 Loan of 286.75 x 10 m or
m 6
3 V (10
D -100 >1m /s possible extraction within 6 years
DV = 286.75 106 m3
-150
-200
-250 Courtesy of V.Ristic 1-Jan-61 1-Jan-63 1-Jan-65 1-Jan-67 1-Jan-69 1-Jan-71 1-Jan-73 1-Jan-75 1-Jan-77 1-Jan-79 1-Jan-81 1-Jan-83 1-Jan-85 1-Jan-87 1-Jan-89 1-Jan-91 1-Jan-93 1-Jan-95 1-Jan-97 1-Jan-99 Courtesy of I.Jemcov GIS based physical modeling
Courtesy of S. Milanovic 4. Regulation projects – SEE experience
Slovakia: Jergaly spring for Banska Bystrica (Kullman E., 1984) Serbia: Several successful regulation projects (Stevanovic et al. 2005) Regional water system "Bogovina"
242 spring Mrljis 241 River Crni Timok 240.24 239.98 239.43 240 239.98 1 239.86 239.42 239.37 2 239.36 239.18 239 238.77 238.78 3 239.76 238.60 238.2. 237.95 238.22 238 237.4
237 236.70
236
1 - static S.W.L.
2 - 27.11. 10h24’ Dynamic 3 - 28.11. 13h50’ G.W.L.
The largest system for aquifer control constructed as a “transitional solution” that supply the towns of the Timok region / East Serbia (Bor, Zaječar, Negotin, Boljevac). Four extraction wells ~ 100m deep were drilled. Several performed pumping tests verified the capacities ranking 50 to 110 l/s per well. An amount of 240-320 l/s was pumped out during the simultaneous test of all wells, producing the depression in the Mrljiš spring zone of less than 2 m (low flow water period). Optimal extraction rate of the source, as compared to the minimal springflow of Mrljiš, has increased almost four-fold. Case example Krupac Modro oko / source of Niš
It is one of the five karstic springs tapped for the water supply of Niš, the second largest town of Serbia. It drains southern part of Svljiške planine mts. (>100 km2), and is characterized by high discharge variation ~ 40 - 11,000 l/s. Undertaken aqua-speleological exploration of deep siphonal channels enabled to install the high capacity pumps and to conduct longer pumping test. Tapping of a large karstic channel deep under the point of natural discharge (60 m) enable six times higher extraction than extreme minimal natural springflow is. Croatia – Proposed large underground reservoir for Dubrovnik
Ombla project New intake for Montenegro coast
Sublacustrian spring Bolje sestre 3 Qmin = 2.3 m /s The total pipeline length is 140 km.
The system is planned for a maximum capacity of 1.5 m3/s in two stages.
The water discharges through several registered points near the shore.
Order: Avoid mixture of water
Complex investigation programme included: hydrology, geophysical survey (geoelectric tomography and electromagnetic VLF method),drilling, tracing tests, hydrogeological mapping, diving, permanent sampling and analyses of the water quality (biological, chemical, radiological).
Specific intake - The concrete elliptical coffer dam will cover an area of some 300 m2 and will have a rubber gate spillway
Albanian – Italian water deal (proposal)
The Bistrica spring system, the largest in Albania (Eftimi,), drains the 440 km2 Gjere Mountain karst 3 massif, Qav 18.4 m /s. Undersea water project proposed for supplying the Puglia region (South Italy). The problems of water quality in SEE karst centre on two main concerns:
1. Aquifer vulnerability and high risk of pollution; 2. Intrusion of salty water (along the coast).
Karstic waters: Extremely vulnerable sources. The problem is greater along the coast due to the many pollutants present there, untreated wastewater, and improper disposal of solid wastes. Fast- growing tourist areas in Montenegro and in Albania are particularly in danger, and during the last few years systematic action to construct modern regional municipal landfills has started.
Case examples of difficult management along coastal area: Pollution (Timavo, Vlore) or Specific sanitary protection zones (Rizana, Rijecina).
There are also a few cases where large springs have been impounded and devastated by artificial reservoirs. To ensure sustainable development within and around the karst environment :
The important aspects such as: water management and control of karst aquifers, protection measures against the potential pollution of karstic surfaces and groundwater, construction of man-made structures in karst and their influence on the environment, protection of geo- and bio-heritage objects (e.g. springs, caves, sinkholes, rare endemic species etc.) required careful studies and mitigation measures How to optimizing water supply? Role of karstic groundwater in SEE?
The majority of countries of SEE is still passing through economical and political transitions regardless their status, either EU member or still waiting for the membership. Water practice:
A. water supply system (WSS) remains in public sector and is manipulated by the state,
B. WSS been fully or partly privatized.
Whatever case there is always space for improvement and better management of WSS. Currently, the trend of decline consumption of drinking water is present in many countries of the region as result of:
the price of water; demographic situation; transition of industrial sector; applied measures in water infrastructure maintenance; improved public awareness to rationalize consumption as result of education and advertisement.
Case example: In Slovakia in 2000 the volume of produced drinking water was reduced for drinking purposes by 31% as compared with 1990. An adequate management of water resources and adapted policy should be primary based on:
insurance of safe drinking water supply,
balance of extracted and available resources following their replenishment potential,
prevention of water sources further deterioration,
protection of water ecosystems, and
sustainable use of both, ground and surface waters artificially regulated (when appropriate). Following the actual social and human lifekind in Europe, economic transition and privatization of public sector there is great challenge for the water management in decades to come. Required optimal International waters transboundary water management:
Recently finished wars, new states and newly-created boundaries in the Balkans and SE Europe, at the centre of which is the former Yugoslavia, have given rise to many questions regarding common and optimal water strategy in the region. However, during the last two or three years many initiatives and concrete actions have been undertaken and now provide an optimistic ambience for future work and cooperation. To learn from the World Commission on Dams (WCD):
Maintain seasonality of flow Maintain discharge volume Sustain water quality Apply high EIA (environmental impact assessment) standards Monitor the impacts... Thank you