Waters of springs discharging from local groundwater-flow systems are normally of low salinity with a temperature close to the mean annual air temperature. In contrast, water of the springs discharging from regional groundwater flow systems may be highly mineralized and have elevated temperatures.
The UAE springs tend to discharge from local and intermediate groundwater-flow systems. These include mineralized and thermal springs with therapeutic value. Khatt springs belong to this category, and have been utilized as recreational and touristic sites. The high-temperature water of springs is related to deep circulation of groundwater. Khatt springs have been used by the local Bedouin tribes and visiting pilgrims for centuries as a curative and medicinal source. Today there are a few hotels in the vicinity catering for the modern day “pilgrims” and a very nice facility has been developed at a number of the pools.
How are Hot Springs Created?
Hot or thermal springs are defined as springs where the temperature of water lies significantly above the mean annual air temperature of the region. As rain falls on the surrounding peaks, it percolated into the rather porous sedimentary rocks. As it descends through the rock, it picks up a variety of materials, everything from radium to sulphur. Also, as it moves further beneath the surface, it heats up from the primal heat of the Earth. Eventually, it encounters a large thrust fault, or crack. As water descends behind it, it forces the now heated water to ascend along the fault-line to surface as a hot or warm spring. Also critical in the creation of a hot spring, is an express route to the surface. If the water moves slowly from depth to the surface, it will cool back down before it bubbles out as a spring. Luckily, since many of these springs occur in limestone formations, The openings allowing the water to the surface may be enlarged by dissolving of the limestone to create a virtual pipeline to the surface. This assures a quick trip and warm waters.
The Khatt Hot Springs
Khatt springs area is one of the most prominent springs inside UAE and situated at the extreme east of the gravel plains where it meets the foot hills of the Mountain range.There are two main springs in this area – the northern and southern. The most interesting feature of these springs is the high temperature of the water. The difference between the temperature of the spring water and that of groundwater in the surrounding area suggests that the former issues from a considerable depth; perhaps about 300 m below ground level. The area around the springs has sedimentary rocks with high limestone content.
Water flowing out from Khatt springs has been used for traditional bathing and medication till 1979 when it further developed to be a major bathing and recreation site in Ras Al Khaimah Emirate. The outflow of pools in addition to water flowing from other sources like small springs and hand-dug wells are drained into an intricate system of lined channels and falajs to supports a substantial cultivation of date palms and other market products.
Due to the drought conditions prevailed in the period 1998-2004 together with the necessity of intensive groundwater exploitation for irrigation purposes, the outflow from the northern spring was not enough for keeping the temperature in the swimming pools to the desired level due to the relatively long time of water residence time in the pool. This also led to deteriorating the environmental conditions in the recreational park around the pool and the spread of mosquitoes.
The What about the local geology?
This part of the UAE lies on the western side of the Fujairah mountain range that stretches from the Omani Hajars all the way up the eastern Indian Ocean coast to the Mussandam peninsula. There has been a lot of upliftment from the small Arabian plate being squeezed between the African and Eurasian tectonic plates. If you have travelled to either central Oman (around Nizwa and Muscat) – or Mussandam – you will notice evidence of this action along the entire length with folds and localized faults. Here at Khatt, the layers are not so seriously folded with tilting being more prevalent. If you follow near by Wadi Bih or Wadi Biah to find some of the other nearby traditional caches – you can notice a change in rock colouration and fold incidence. The obduction of the rocks (one plate moving below another) leads to areas that have a higher than normal geological activity and the possibility of surface water being heated as it percolates downwards is increased. As this warmed water rises to the surface, hot springs can be found. Jebel Hafit near Al Ain and Ain Ghala near Muscat are just two examples of this in the region.
The spring area lies on the western side of the Northern Oman Mountains, which are comprised of the Jurassic to Cretaceous Musandam Group limestone. These mountains rise above the western Jiri coastal plain, which consists of late Tertiary to Recent alluvial sediments overlying the late Cretaceous Juweiza Formation. The Juweiza is a flysch-like sequence of marls and shales with varying admixtures of coarse detrital debris of chert, basic igneous rocks, and limestone. The area has been subjected to two major tectonic events. These are the thrusting of the Hawasina Formations and the Samail Ophiolite over the Musandam limestone in the Upper Cretaceous and then the formation of the Oman Mountains due to folding, faulting and thrusting in the mid Tertiary. This resulted in the formation of the major northeast-trending anticlinal structure through the Musandam Mountains, the Hagab Thrust fault along the western edge of the mountains and the Jiri plain, and the Dibba Zone to the southeast, with the Batha Mahani thrust running along the valley of Wadi Tawiyean. Consequently, the Musandam limestone is strongly faulted, with major trends running northeast (parallel to the Dibba Zone thrusts), north, and northwest.Two hydraulically connected groundwater aquifers can be identified as follows:
Quaternary aquifer which is composed of the gravel plain of recent silts and conglomerates and meets the mountain front at a high angle. This layer is overlying the thick Juweiza formation which is generally of low permeability and thus acting as aquitard rather than an aquifer.
Carbonate aquifer which refer to the exposed thick Musandam limestone of Jurassic - Cretaceous age in the mountains.
These carbonate layers are composed of well jointed, karst weathered, thin bedded, nodular, fragmental and porcellanous dolomitic limestone and also limestone interbedded with calcareous shales. These beds dip at a very high angle, up to 90º, to the west and have been planed off, probably by marine erosion, at about 600 feet above sea level for about two km into the mountain front. Various north-south trending folds can be seen on the aerial photographs on the western strip of the main mountain massif. At Khatt, these beds are linked to the gravel plain layers in the following ways:
a) as the western flank of a north-south trending anticline;
b) as the eastern upthrow side of a north-south trending fault bounding the mountain front;
c) as the ‘nose’ of a thrust of the Mesozoic limestone facies to the west over a radiolarite-serpentinite fades, as exposed in Wadi Hagil.
(Acknowledgements: THREE-DIMENSIONAL GEOLOGICAL AND GROUNDWATER FLOW MODELING OF DROUGHT IMPACT AND RECHARGE POTENTIALITY IN KHATT SPRINGS AREA, RAS AL KHAIMAH EMIRATE, UAE - P. Wycisk, M. Al Assam, S. Akram, M. Al Mulla, D. Schlesier, A. Sefelnasr, N. B. Al Suwaidi, M.S. Al Mehrizi, and A. Ebraheem)
To log this earth cache:
The published coordinates will take you to the Khatt Hot Springs bathing and recreation site. There is an entrance fee if you want to take a dip in the pool. However, entry is free if you are visiting just to see the pools. Photography inside is not allowed, please be mindful of this – including outside where photography of people, without permission, in particular can be taken incorrectly. Please be mindful of other people and their privacy at the springs.
To log your find you must visit the hot springs pool and answer the following questions via email to the cache developer. You may log your visit prior to approval, but e-mail submissions that do not meet the criteria will be deleted.
1. Describe the bottom of the pool.
2. Describe the smell of the water. what clue does this give to the source of the water?
3. Approximate temperature of water.
4. Based on your observations, looking at any signs on site and speaking to any people on site –mention anything about the mineral content of the water that you have learned.
5. Give your impressions of the area and some observations that you made about this location. Specifically describe the mountains and rocks to the east of the site (behind the castle-like Khatt Springs Hotel above you). Also describe if you have noticed how local geology/geomorphology has influenced early human settlements.
Please post a photograph on the site with your log of your GPSr near GZ (This is optional).
