Objectives include: (a) development of a methodology for the quantification of the concept of vulnerability of groundwater drinking wells, in a probabilistic 
framework; (b) application of this strategy to a specific situation and a selected site and simulation of the impact of the obtained solution in decision-making 
policies; (c) definition of the philosophy of risk assessment for well fields in a stochastic context and (d) production of guidelines for drinking water companies 
and Environmental Agencies on how to reduce uncertainty on heads/fluxes prediction by geological field investigations and monitoring of groundwater heads/concentrations. 
We will attack the problem on different fronts: (a) theoretical/conceptual; (b) laboratory and field scale; (c) deterministic and stochastic model development 
of synthetic and real-world cases. Numerical Monte Carlo (MC) techniques will be employed, addressing issues such as (a) development of efficient algorithms 
for MC simulations of catchments in 3D using alternative methods of particle tracking and Kolmogorov backward equation; (b) clarification of conditioning 
formalisms, through analysis of the importance of conditioning data in order to reduce the uncertainty of well catchments; (c) adoption and development of 
inverse methods that can use a variety of data types to decrease uncertainty about aquifer properties and wellhead regions of influence. Algorithms for optimum 
unbiased prediction (together with corresponding prediction errors) of head and fluxes leading to identification of well catchments will be developed according 
to the novel nonlocal formalism of groundwater flow moment equations. Laboratory and field data will be collected and analysed. A traditional deterministic 
model will be applied to a selected field situation and results will be evaluated in light of probabilistic concepts. Our new numerical schemes and methodologies 
will be demonstrated in selected practical situations. 
            

The code SicWin (Stocastich IsoChrones) has been developed within the Project W-SAHaRA (Stochastic Analysis of Well-Head Protection and Risk Assessment, 
supported by the EU within the Fifth Framework, Key Action Water. It simulates pumping of a single well in a uniform base flow and the related spatial distribution 
of isochrones of an ideal solute. The well is fully penetrating a confined aquifer of given thickness and infinite extent. Aquifer hydraulic conductivity 
is simulated as a random constant, whose value can be drawn from either a Uniform or a Log-normal probability distribution, chosen by the user. 
            

W-SAHaRA aimed to develop guidelines for predicting the extent of drinking wells protection region in natural heterogeneous formations and assessing the 
associated prediction errors in a probabilistic framewrok.    
    
The following producst are available:    
    
- Software producted by the consortium (SicWin)    
- publication list    
- A review of stochastic methods for well capture zone determination    
- Downloadable Summaries for different Workpackages