Consulting

Unders­tan­ding karst ground­wa­ter requires a 3D assess­ment of the geo­lo­gy. KARSYS is a deduc­tive approach based on the geo­lo­gy of a site and the hydrau­lic prin­ciples gover­ning kars­ti­fi­ca­tion. Once a site is defi­ned, SISKA deploys a 4 step approach : (i) iden­ti­fying the kars­tic pro­per­ties of the aqui­fers, (ii) esta­bli­shing a 3D geo­lo­gi­cal model of aqui­fer units, (iii) gene­ra­ting a 3D hydro­geo­lo­gi­cal model through inte­gra­tion of hydro­lo­gi­cal data and (iv) iden­ti­fi­ca­tion and deli­mi­ta­tion of flow sys­tems.
This results in :

• the deli­mi­ta­tion of spring basins ;
• the volu­me­tric assess­ment of ground­wa­ter resources ;
• a model of under­ground water flow paths.

Visual­KAR­SYS, is a free online ser­vice for buil­ding and vie­wing KARSYS models.

Karst­MOD (hydro­lo­gi­cal and hydrau­lic models) makes it pos­sible to simu­late ground­wa­ter dyna­mics quan­ti­ta­ti­ve­ly, and assess recharge (effec­tive infil­tra­tion), sto­rage and flow at one or more out­lets.

SISKA applies methods and tools to stu­dy the vul­ne­ra­bi­li­ty of ground­wa­ter,the deli­mi­ta­tion of pro­tec­tion zones and the search for sources of pol­lu­tion.

In col­la­bo­ra­tion with other spe­cia­list part­ners, SISKA offers solu­tions for pros­pec­ting and exploi­ting ground­wa­ter. This includes the ana­ly­sis of spring flows and simu­la­ting of flows under dif­ferent sce­na­rios (meteo­ro­lo­gi­cal, anthro­po­ge­nic impacts, exploi­ta­tion stra­te­gies).

SISKA pro­poses spe­ci­fic approaches for asses­sing the hazards karst poses on construc­tion and various acti­vi­ties.

Civil engineering and karst

During construc­tion, par­ti­cu­lar­ly under­ground (tun­nels, gal­le­ries, reser­voirs…), the kars­tic envi­ron­ment can present struc­tu­ral pro­blems. These include unex­pec­ted voids, pres­su­ri­zed water and the pre­sence of poor­ly conso­li­da­ted sedi­ments. Using the Karst ALEA, the SISKA can pre­dict poten­tial hazardsand pro­pose pro­tec­tive mea­sures to mini­mise them, and recom­men­da­tions to manage them in the event of a pro­blem.

Wind turbines and karst

SISKA is deve­lo­ping methods for asses­sing and sup­por­ting the ins­tal­la­tion of wind tur­bines in karst regions. The aim is to mini­mise the risks of karst to infra­struc­ture sta­bi­li­ty. An infor­ma­tio­nal bro­chure on this issue has been publi­shed by the SSS.

Infiltrations

In an urban kars­tic envi­ron­ment, the fede­ral recom­men­da­tion to infil­trate grey water (roof and road water) is pro­ble­ma­tic because this infil­tra­tion may faci­li­tate col­lapses. SISKA can draw up col­lapse hazard maps and assess­ments. In the event of a col­lapse, tar­ge­ted recom­men­da­tions can be issued.

If infil­tra­tion sites are selec­ted, SISKA can issue recom­men­da­tions on accep­table infil­tra­tion flow rates and condi­tions.

Collapse hazards

The kars­tic sub­sur­face contains nume­rous cavi­ties, some­times cove­red by a thin layer of soil. Col­lapses are the­re­fore not uncom­mon. SISKA can pro­duce site spe­ci­fic col­lapse hazard maps and assess­ments.

Geothermal

The spe­ci­fic cha­rac­te­ris­tics of karst can lead to poor constraints on geo­ther­mal pro­jects. Indeed, due to the signi­fi­cant cir­cu­la­tion of air and water, kars­tic mas­sifs are col­der than other envi­ron­ments. Howe­ver, kars­tic springs drain geo­ther­mal heat and represent an inter­es­ting resource. SISKA has unique exper­tise that enables it to assess ener­gy poten­tial and deve­lop a stra­te­gy for geo­ther­mal exploi­ta­tion in car­bo­nate regions.

SISKA can pre­pare pres­crip­tion maps for the ins­tal­la­tion of geo­ther­mal probes based on ground­wa­ter vul­ne­ra­bi­li­ty cri­te­ria.

The construc­tion pro­jects and various human acti­vi­ties (tun­nels, gal­le­ries, roads, wind tur­bines, geo­ther­mal ener­gy, infil­tra­tion of grey water, etc.) can have an impact on the kars­tic envi­ron­ment. SISKA is spe­cia­li­sed in asses­sing and mini­mi­sing these impacts in accor­dance with the Ordi­nance on Envi­ron­men­tal Impact Assess­ment (OEIE).

SISKA has deve­lo­ped a series of tools and methods for such assess­ments (Visual KARSYS, Karst ALEA and others).

Impact on groundwater

In kars­tic envi­ron­ments, almost all rain­wa­ter infil­trates the sub­soil and, after a few days to weeks, emerges from springs that then feed rivers. Deve­lop­ments and struc­tures can modi­fy the water’s flow regime and qua­li­ty. These changes can be cri­ti­cal for drin­king water catch­ments, rivers and under­ground aqua­tic fau­na. SISKA can assess these impacts and seek solu­tions that mini­mise them.

Impact on underground fauna

The under­ground envi­ron­ment is home to a spe­ci­fic and varied fau­na, inclu­ding seve­ral ende­mic spe­cies. Les habi­tats sou­ter­rains sont très stables car peu connec­tés aux varia­tions exté­rieures (cli­mat, urba­ni­sa­tion, etc.). Par contre leurs habi­tants sont très sen­sibles aux chan­ge­ments. L’ISSKA peut éva­luer la faune pré­sente, la sen­si­bi­li­té des habi­tats et les influences poten­tielles ou effec­tives d’un pro­jet d’amenagement ou de construc­tion.

Impact on the underground climate

The tem­pe­ra­ture and humi­di­ty (>98%) under­ground is almost constant year-round. Any dis­rup­tion to these cli­ma­tic condi­tions will have an impact on the cave, the fau­na and any archaeo­lo­gi­cal arte­facts found there. Fur­ther­more, the under­ground atmos­phere is often enri­ched with CO₂ and radon, which can cause pro­blems if the cave is occu­pied for long per­iods (e.g. archaeo­lo­gi­cal exca­va­tions, tou­rist visits). SISKA can mea­sure and moni­tor the cha­rac­te­ris­tics of an under­ground cli­mate sys­tem and can the­re­fore assess the impact of a deve­lop­ment or construc­tion pro­ject on cave cli­mate.

Impact on the karstic landscape

The karst land­scape is a heri­tage reco­gni­sed throu­ghout the world (18 sites lis­ted on the World Heri­tage List). UNESCO World Heri­tage Site and nume­rous others are lis­ted in the fede­ral land­scape inven­to­ry). In Swit­zer­land, sin­kholes, potholes and caves are often not expli­cit­ly inven­to­ried, even though they form part of the coun­try’s natu­ral heri­tage. SISKA can iden­ti­fy these objects, assess them and seek solu­tions to mini­mise poten­tial impacts on these fea­tures.

The Karst ALEA method was deve­lo­ped spe­ci­fi­cal­ly to assess the pro­blems posed by kars­tic envi­ron­ments during the construc­tion of a struc­ture and the impact of the pro­ject on the envi­ron­ment. It can be used to pre­dict the posi­tion and cha­rac­te­ris­tics of kars­tic cavi­ties in a limes­tone mas­sif. 

It also serves as a basis for dra­wing up col­lapse hazard maps.

Link to applied methods Karst ALEA