- Maintenance for the site developed as such must be provided for, especially by defining a safety perimeter around it in order to protect it from all types of pollution (fertilizers, animal droppings) that would pollute the water collected. Possibly, in order to protect the facility from erosion, diversion ditches for runoff flows must be installed.

- The quality of the water must be checked before and after the work, and then periodically.

- The level of water in the collection basin must always be under the level of emergence of the spring before the beginning of the work, otherwise the water from the spring will no longer be able to be collected. It is therefore more prudent to also provide an overflow pipe at the exit for the basin Checking purity

- The population should be closely involved in choosing, creating and in monitoring the spring

_Properly designed slope protection and stabilization has to include two components: a vegetational-biological and a mechanical-structural component. For maximum effect, both components must be integrally planned prior to road construction.The function of root systems of live plants on shallow soils on steep slopes is that of a binder for individual soil particles or aggregates.The structural-mechanical component can consist of conventional retaining walls, either the gravity or cantilever type, or a reinforced earth structure. Structural-mechanical stabilization techniques are called for in cases where the potential for deep-seated slope movement or high, lateral earth stresses exists.

http://www.wikiwater.fr/e3-water-catchment-and-simple.html

Carlos,

Please protect the recharge area of the spring from human interference. Although it is difficult, the recharge area could be declared as 'protected' by the local Government. The spring head could be protected with the help of barbed wire. But, please do not try to modify the mouth of spring emergence; the spring may  vanish somewhere.. Best,

Article Springs in a headwater basin in the Deccan Trap country of t...

Thank you Pouneh and thank you Pradeep for your answers. However, my problem is not about the measures to protect the area but how to define this one. In my country we have lots of small springs and galleries used for human consumption. They are located in the slopes of mountains where the main lithologies are granites and shists.  A methodology that I used is to estimate the total annual discharge and estimate the area needed for maintain this discharge. For this we need to assume some recharge rate and to know the mean precipitation. The perimeter surrounding the area could be defined as a circumference touching the water point or has some other form (ellipse or leaf like). However I am not confident that this is the correct methodology. I was hoping that we could use some equation that helps to define the perimeter in a more sound way.

To improve our understanding, therefore, we investigate two factors that might contribute to local variation in density: bedrock geology and topographic slope.

heterogeneities to be a driver in lavaka formation. feldspathic and micaceous rocks, such as gneisses, granites, and schists,would provide good lavaka(hole) substrate because their components are resistant to weathering. Mafic and ultramafic rocks, would not generate lavakas because greater degrees of weathering of ferromagnesian minerals would render the saprolitic carapace(saprolitic:porous rock, often rich in clay, carapace:exoskeleton or shell in a number of animal) too weak to support the steep walls of lavakas.

show that the proportion of sand and silt can dramatically affect the type and volume of gully erosion.

Estimating peak flows at ungaged sites on regulated streams, peak flows on regulated streams are dependent upon variable human activities.Precipitation patterns strongly affect the magnitude and timing of peak flows. Seasonally changing conditions, such as evapotranspiration rates, antecedent soil moisture, and the extent, duration, and intensity of storm systems affect flood response in a given drainage basin. average peak flow (Qtw) calculate by use of the equation :

logQw=10(log(Qto)w)+log(Qtr)(we)/(w+we)

http://pubs.usgs.gov/wri/wri034180/pdf/wri034180.pdf

Each and every spring is a unique outflow of water generated by complex open ecosystems operating dynamically above, below and at ground level. Consequently, closed system scientific methods based on linear cause and effect logic are strictly invalid.

To identify and protect the source zone of springs requires mapping and modelling (a) regoliths and their geomorphologies (b) habitats and their communities and (c) meteorological processes and their net energy flux at the appropriate scale ~ this will establish the spatial parameters, ecological processes and energy regimes maintaining the spring... Typically, a transdisciplinary watershed GiS is developed for mapping and modelling the watershed.

NB sometimes the spring is fed by aquifer leads from a great distance ~ many kilometers. Springs in Baktapur (Kathmandu) Nepal for example are fed by aquifer leads from mountains more than 20 kms away...This is not unusual.

The water release rates from springs is controlled by algae/cryptogam bioseals. These seals are as fragile as they are inconspicuous.... Just one grazing hard hoof animal can destroy aquifer spring bioseals in a day.... And grazing animals love the sweet nutritious fodder found at springs sites....As a result they are the first sites compromised by grazing herds. The damage to bioseals from grazing livestock can take 10-30 years to heal and reseal the spring...

Zero grazing farming systems are essential in rangeland watersheds to protect springs and aquifers from bleeding dry and dying... See Habitat and Riparian Management in Rangeland Ecosystems in UNESCO EOLSS 2009....

If you can clearly define a contribution area based on topography, I would use the DEM and delineate the entire contributing basin. WhAEM (free) is useful in delineating protection areas and can be used with minimal data.

http://www.epa.gov/exposure-assessment-models/whaem2000

Good that you are aware of the vital aspect to protect the springs. A mutli parameters approach is necessary and the involvment of the stakeholders as well as the end users is capital for a sustainable plan. What about the present state of water purity and the kind of feared pollution?? In any case the larger part  of the recharge area must be considered for selective and controled activities either for human or animal purpouses. a system of permanent contrôle of the water quality is to be installed...so to quantify the efficiency of the taken measures... 

Dear all

First I would like to thank you for your interest in this subject.

In my country there is already regulatations preventing some activities in the recharge zone of a water source used for human supply. However in many cases one has difficulties to define that zone. This is particularly true in springs located in mountain slopes where the flow is not horizontal preventing the use of many mathematical models as WhAEM .

In managing national forests, our activities of harvesting trees typically have no identifiable effect on springs, except when removing vegetation, there may be more flow than before.  In conversion of vegetation types, pine trees typically use the most water, hardwoods next and grasses the least of the three.  Most of our mountainous springs in the Blue Ridge Mtns of SC and GA where I have worked are not well defined as to their recharge areas and the potential extent of their need for protection.  I think if you have critical water sources dependent on the springs, your best bet would be to consult with a geologist familiar with or who has mapped the area, knows the stratigraphy, like folding, faults, strikes and dips, familiarity with reading the surface and relating that do the subsurface.  It is not far fetched to consider that the area of potential influence may be beyond the surface hydrology, as I remember one instance where the stratigraphy dipped from one side of the mountain to the other, and more flow and instability of soils was found on the side where the stratigraphy was dipping to.  For most normal operations within the forest, we typically buffer the spring with 100 feet of no or minimal cutting, no skidders, etc.  This is with the recognition that most of our forest areas have been cut over more than once, and some may have even been locally farmed in years past.  I am also somewhat familiar with karst springs in Missouri Ozarks.  Years ago, Dr. Tom Alley developed a cookbook on tracing underground water flow and springs, and he found instances where fluorescent dye was added in one surface drainage system, and showed up in another.  But you don't have that type of geology.  Since the springs sound critical to your communities, I would get a good geologist and have the critical vicinity/ies mapped.  Since the vibration of heavy equipment has increased effects during wet soil conditions, I would have activities done in the drier seasons.  And I know that this may sound far fetched for a scientist, but a geologist in Oregon showed me how to bend two steel welding rods and douse for underground water.  When I passed over the underground flow path, the rods came together or apart, depending on the direction of flow.  It was a bit eerie, but obviously there are some magnetic fields that underground moving water gives off.  The geologist in Oregon, Joe Cornell of the Siskiyou National Forest used this information to directional drill into the slope with perforated plastic pipe to drain unstable areas to avoid or release the potential for failure if there were signs like tilting trees, etc.  I don't know that anyone can prescribe to you exactly what needs to be done without a lot more information.  One more thing, I would get some readings one the changes in flow over time, at least a few cycles of wet and dry periods, with specific conductance and perhaps other water quality indicators.  I am reminded by a paper by CG Garrett, VM Valava, TJ Callahan and ML Jones, 2011 Groundwater-surface water interactions in a lowland watershed source contributions to streamflow in Hydrological Processes 10.1002/hyp.8257 in the coastal plain where they were able to separate out estimates of rain, shallow and ground water.  The end member methods used might help you discover and determine whether the primary sources are rainfall or shallow quickflow, shallow underground or deep groundwater sources.   

Dear William,

Many thanks for your response. As you said it is always important to look at the geology of the area. As I am hydrogeologist and also a geologist, I usually make a careful survey of the area. I am only interested in a particular geologic environment (granites and schists) where many springs are used for water supply. Whenever possible I make a survey of the fractures and other important structural features which could help to define the recharge area. Some of the areas are covered by forests but others are crossed by roads or are close to dwellings.

In the case of karst springs I have also some experience as I worked with other colleagues in defining the protection area of some important springs. I also participated in a European project dealing with the protection of karst aquifers (Project COST 65).

Your welcome.  I did not mention LiDAR, seismic, and ground penetrating radar as other possible useful tools.  I am familiar with both geology types, but my training is more surface hydrology than geology.  But I have always been interested in where springs or headwaters emerge, whether springs or not.  We have found many uses for LiDAR as it can detect many surface features that are difficult to see in heavily forested and vegetated areas.  If I had an spring of major concern, and the dip of the geology toward the spring was a 20 degree angle, I would probably consider at least all surface areas that could receive and absorb rainfall and deliver it to that subsurface feature typically bedrock or restrictive layer.  So essentially, this may not only include the surface drainage area, but also potentially areas on the backside of the mountain that could percolate water to the restricting geologic surface that concentrates flow to the springhead.  If you have roads, ditches or other hydrologic modifications that move water into the consideration area, you might have to expand it.  Such as if a road captures road drainage and delivers it into the area, it would be considered.  Geologic fractures and failure areas are prime areas for recharge as are surface depressions such as streams and channels.  LiDAR can help see things remotely that normally may not be discovered without detailed survey or a very good eye, with the caveat that topographic shading can be a problem with aerial LiDAR accuracy relative to incised streams such as gullies (James et al, 2007 - one of the papers I co-authored).  Inventory of springheads and also perennial headwaters (ie, streams with perennial indicators such as diverse aquatic insects) may be useful when you compare them with geology, elevations, and potential contributing area.  In the blue ridge mountains, we have some perennial springs near a ridge.  One can assume in those instances that either the subsurface stratigraphy is very focused to capture and deliver water to the surface at the springhead or there is other unknown groundwater sources and conduits that have sufficient head to push water toward this location.  The residence time of water often exhibits chemical changes that may help differentiate.  I don't know if I have uploaded the 1975 paper about springs in Missouri Ozarks (karst terrain), but it compared water quality of the small catchment water quality at the University Forest vs flow with various other springs with water quality data.  The information shows as flow rate increases (cfs) many of the elements decrease due to reduced subsurface residence time.  If the springhead you want to protect is water source for say one family, you probably are not going to study it to the same degree or protect a large area from activity.  You still will want to use reasonable protective measures such as buffering the springhead and less intensive ground disturbing activities.  If the area has been farmed or harvested in the past, and the spring still functions, why would there be questions unless the vicinity is being developed or hydrologically modified?  If the spring serves a community as the only viable source, is used to bottle and sell spring water of high quality, the value and risk goes way up.  More study is justified.  More protection may not necessarily be needed, but is justified based on the risk of loss is so much higher.  Prioritize and collect data on the ones where you can get funding.  The data from those springs will probably help understand those that are not studied in detail.  Every time those involved with your research or even spring users with some training visit a spring (GPS location) in your area, I would have them an estimate of flow, specific conductance and any other routine tests you can easily do, such as maybe pH.  If they can afford a flume or v notch weir, transducers are relatively inexpensive to record water levels and convert to flow.  Add in water quality recording devices as sonde, you may get quite a few and some even measure water level that has to be adjusted to barometric pressure.  The recording sonde setup might be $2-3 thousand to get pH, specific conductivity, TDS, water level and salinity plus recording barometric pressure detector (I was doing a study on tidal influence to a wilderness area).  I did not get into wells, but they can be very useful for measuring changes in groundwater level and quality, and differentiating between surface aquifer and subsurface aquifer(s). 

Dear William,

Many thanks for your detailed text and suggestions. I just downloaded your paper about quality of Missouri Ozarks. I think that your suggestion to use LiDAR could be very useful as we have the equipment and people used to work with it. In one case that I was involved, where a highway cross the protection area, measures were taken in order to drive waters from road drainage out of the area.

Very often the problem we face is the insuffiency of funds to do a detailed study because the in many areas the number of springs and other sources of groundwater are very numerous. The discharge of them is almost always very small.

Great.  I understand.  One thing to consider, small discharges suggest slow movement of water through substrates and perhaps that may mean more filtering.  Geologist or groundwater hydrologists may set up wells for water table to get head differences, and from that they can calculate porosity and transmissivity of materials.  Springs that emerge from the springhead like a major stream or river, you have to wonder.  It may be the best water ever, but without understanding its sources and function, you have to be more careful in determining potential pollution sources.  At least, this makes sense to me.  Also the small spring or perennial seep may serve a family or two, not a community.  If your restricting strata dips at 20 degrees, unless you are on top of mountain, there are going to be places that the ground level is close to this strata, and other areas where you have many feet for surface water to pass through to get to the strata.  If the soil has good filtering capacity, you should be good.  If you have skeletal soils, rubble, lots of gaps or discontinuities in the surface, or where water flows then totally disappears, you just have to be more careful.  I am more a surface hydrologist and its always good to get other opinions, especially from those that work in your area.

Dear Carlos,

I think that the general solution does not exist but it should be found case by case in accordance with the local hydrogeology.

perhaps the best solution is to tap the groundwater by horizontal wells.

Dear Gianpietro

I agree with you. As a matter of fact the solution that you suggest is very common in the geologic environment in discussion.