Chapter 21C. Geohydrologic Summary of the Khanneshin 

Carbonatite Area of Interest

By Michael P. Chornack and Thomas J. Mack

21C.1 Introduction

This chapter describes the geohydrology of the Khanneshin carbonatite area of interest (AOI) in 

Afghanistan identified by Peters and others (2007). The AOI occupies 7,771 km2 (square kilometers) 

and is located primarily in the Dishu, Garmser, and Reg Districts of Helmand Province (fig. 21C–1a,b). 

A small area of the northwestern most part of the AOI, about 20 km2

, is in the Chahar Burja District of 

Nimroz Province. The Khanneshin volcano is a topographic high formed by extrusive volcanic rocks in 

the center of the AOI (fig. 21C–1a). The Khanneshin volcano is approximately 9.5 km (kilometers) 

south of the Helmand River. The AOI is in the western part of the Registan (land of sand), an area that is 

characterized by active dunes (Whitney, 2006). Lashkar Gah, the Helmand Province center, is 

approximately 130 km northeast of the AOI. 

Water is needed not only to process mineral resources in Afghanistan, but also to supply existing 

communities and the associated community growth that may accompany a developing mining economy. 

Information on the climate, vegetation, topography, and demographics of the AOI is summarized to 

provide information on the seasonal availability of, and seasonal demands for, water. The geohydrology 

of the AOI is described through the use of maps of streams and irrigated areas, generalized 

geohydrology and topography, and well locations. The results of lineament analyses are presented to 

identify areas where the rock may be more fractured than in other areas, which may be an indicator of 

high relative water yield and storage in bedrock aquifers. 

Afghanistan’s recent turbulent history has left many of the traditional archival institutions in 

ruins, and most water-resource and meteorological data-collection activities had stopped by 1980. 

Recently, nongovernmental organizations (NGOs), foreign government agencies, and the Afghan 

government have begun water-resource investigations, and U.S. Geological Survey (USGS) minerals 

teams conducted field reconnaissance work in the AOI in September 2009, and again in August 2010; 

however, these activities and the amount of data collected are limited. This report summarizes the 

satellite imagery and climatic, topographic, geologic, surface-water, and groundwater data available.

Geohydrologic inferences are made on the basis of an integrated analysis of these data and an 

understanding of conditions in other areas of Afghanistan. 

21C.2 Climate and Vegetation

Climate information for the Khanneshin carbonatite AOI is based on data generated for the 

Afghanistan agricultural-meteorological (Agromet) project. Agromet was initiated by the U.S. Agency 

for International Development and the United Nations Food and Agriculture Organization in 2003 to 

establish data-collection stations and develop country-wide agrometeorological services. Scientists with 

the Agromet project are assisting the Afghan Government to collect and analyze agricultural and 

meteorological data as they relate to crop production, irrigation, water supply, energy, and aviation. The 

USGS assumed responsibility for the operation of the project in 2005; by the end of August 2010, 87 

Agromet stations were recording precipitation data and other parameters. Additionally, the Agromet 

project receives data from 18 Afghanistan Meteorological Authority (AMA) weather stations. The 

Agromet project has developed a database that includes data collected at the Agromet stations over the 
Chapter 21C. Geohydrologic Summary of the Khanneshin Carbonatite Area of Interest 1501

past 6 years (2005–2011), data collected at the AMA weather stations, and historical data collected at 

weather stations from 1942 to 1993. Data collected as part of the Agromet project are compiled annually 

by water year (September through August) and are reported in the Afghanistan Agrometeorological 

Seasonal Bulletin (Seasonal Bulletin). Unless otherwise specified, the Agromet data cited in this report 

are from the agricultural season that extends from 1 September, 2009, to 31 August, 2010. 

a 
1502 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

b 

Figure 21C–1. (a) Landsat image showing the location of, and (b) place names, stream names, and streamgage 

station numbers in, the Khanneshin carbonatite area of interest in southern Afghanistan.
Chapter 21C. Geohydrologic Summary of the Khanneshin Carbonatite Area of Interest 1503

The 2009–2010 water year average precipitation recorded at a number of stations in Agromet’s

South Region was 177.8 mm (millimeters) (Ministry of Agriculture, Irrigation, and Livestock, 2010).

The average precipitation for the four Agromet stations located in Helmand Province was 172 mm/yr

(millimeters per year). The station at Zaranj in Nimroz Province, approximately 172 km west-northwest 

of the AOI, recorded 41 mm of precipitation during the 2009–2010 water year (Ministry of Agriculture,

Irrigation, and Livestock, 2010). The prevailing wind direction in this part of Afghanistan is northwest 

to southeast, and then becomes west to east over the AOI (Whitney, 2006). The amount of precipitation

at Zaranj is probably indicative of the precipitation in the AOI.

A climate diagram presented by Whitney (2006, fig. 10) for Deshu (Dishu), a historical

meteorological station about 29 km west of the AOI near the Helmand River with a total of 4 years of 

record prior to 1973, shows an average precipitation of 73 mm and an average temperature of 20.9 °C

(degrees Celsius). The maximum temperature recorded at the Zaranj Agromet station in July 2010 was 

47.6°

C (Ministry of Agriculture, Irrigation, and Livestock, 2010). This was also the maximum 

temperature recorded during the 2009–2010 water year for the South Region (Ministry of Agriculture, 

Irrigation, and Livestock, 2010). The minimum temperature recorded at Zaranj in July 2010 was 23°C 

(Ministry of Agriculture, Irrigation, and Livestock, 2010). The Agromet station at Kandahar

(table 21C–1), about 240 km northeast of the AOI, is the closest Agromet station for which both 

2009–2010 water year and long-term average (LTA) precipitation and temperature data are available 

(Ministry of Agriculture, Irrigation, and Livestock, 2010). The 2009–2010 average monthly high 

temperature at Kandahar was 33.37°C in July 2010 and the average monthly low temperature was 9.29°C 

in December 2009. The LTA high temperature was 31.8°C for July and the LTA low temperature was 

4.8°

C for January.

Evaporation rates were measured at pan evaporation sites in southern Afghanistan in 1964. The 

evaporation rate at Lashkar Gha (fig. 21C–1b), the closest site to the AOI, was 2.8 m/yr (meters per 

year) (Whitney, 2006). As is common in desert environments, the evaporation rates are much greater 

than the precipitation rates.

The area within the flood plain of the Helmand River is extensively irrigated and agriculturally

developed (fig. 21C–2). Native vegetation in the AOI is sparse and is dominated by desert shrubs, 

bushes, and grasses. On upland bedrock surfaces of the Khanneshin volcano, plants grow in fractures in 

the volcanic rocks (fig. 21C–3). Desert plants are also present in places where soil or sediments overlie 

the bedrock, such as in ephemeral stream channels and at bedrock-alluvium contacts. The plants that 

grow in the ephemeral stream channels likely have access to an abundant supply of water throughout the 

year. This water supply is indicated by plants in ephemeral stream channels that show active growth, 

such as green foliage, whereas plants outside the channels are dormant. The vegetation in the desert 

plain surrounding the volcanic cone is sparse. The active dune fields are devoid of vegetation.

The “Potential Natural Vegetation” described in Breckle (2007) is the vegetation cover that 

would be present if it had not been modified by human activity. Today, as a result of continued 

exploitation such as grazing, farming, and deforestation, much of the original natural vegetation is found 

only in a few remote areas of Afghanistan. The destruction of the natural vegetation has resulted in the 

degradation and erosion of the soil cover in some areas. Many areas exhibit signs of long-lasting 

desertification caused by human activity.

The “Map of potential natural vegetation” in Breckle (2007, fig. 2) depicts two vegetation zones 

in the AOI. The Calligonum-Aristida-Sanddesert type vegetation is dominant in the AOI. Haloxylon 

salicornicum-Desert type vegetation is present in the extreme eastern and western parts of the AOI. 

Breckle (2007) states “The deserts of the north, west and south in the Registan and Dasht-i Margo 

contain active sand dune areas and dunes fixed by a rather open vegetation. The flora here is scarcely 

modified by man.”
1504 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Table 21C–1. Annual, long-term annual average, and long-term average minimum and maximum precipitation 

and temperature at the Kandahar Agrometeorological (Agromet) station located 240 km northeast of the 

Khanneshin carbonatite area of interest, Afghanistan.

[AOI, area of interest; km, kilometers; m, meters; mm, millimeters; °C, degrees Celsius]

Precipitation Temperature

Distance 1 1 Long-term average Long-term average 2009– Agromet from AOI Elevation Monthly 2010 Monthly Minimum station center (m) Annual maximum Monthly Maximum and annual minimum and and month (km) (mm) and month mean (°C) month (°C) (mm) month (mm) (°C) (mm)

Kandahar 240 1,020 166 155.5 0 September 49.1 4.8 January 15.9 31.8 July

June January

1

Long-term averages are based on data from 1942 to 1993 and 2005 to 2010 as reported in the Afghanistan 

Agrometeorological Seasonal Bulletin (Ministry of Agriculture, Irrigation, and Livestock, 2010).

21C.3 Demographics

The LandScan database (Oak Ridge National Laboratory, 2010) uses features such as roads or 

other manmade structures to estimate population density. The population density of the Khanneshin 

carbonatite AOI as mapped by LandScan indicates a small, dispersed population (fig. 21C–4). The 

majority of the AOI is uninhabited; where it is inhabited, the population density is in the 26 to 50/km2

range. The areas of higher population density in the AOI, several 1-km2

 pixels with populations of about 

500, are concentrated along the Helmand River. The linear patterns of some of the areas where 

population density is 1 to 5/km2

 south of the Helmand River might indicate roads or trails and are not 

indicative of permanent settlements. These areas may also include temporary camps used by nomadic 

Afghan families or groups. The population density shown in figure 21C–4 has a pixel resolution of 

about 1 km2

 (Oak Ridge National Laboratory, 2010). 

No dwellings or other signs of permanent settlements were observed in the immediate vicinity of 

the Khanneshin volcano, in the Khanneshin Volcano subarea, during site visits. Many settlements were 

observed along the Helmand River (fig. 21C–4) that are supported by irrigation canals that transport 

water from the river to cultivated areas (fig. 21C–2). Adjacent to the river, shallow groundwater from 3 

to 4 m (meters) below ground surface (bgs) is accessed by dug or drilled wells. Hand pumps and electric 

pumps are used to supply water from wells for domestic use and for irrigation. The settlement of 

Khanishin village (fig. 21C–1b) is the district center of Reg District and appears to be the closest 

settlement to the Khanneshin volcano. There are no primary or secondary roads in the AOI and the 

region is served by tracks mapped along both banks of the Helmand River (Afghanistan Information 

Management Service, 2003). Some of the mapped tracks lead north into the Dasht-i Margo, but none are 

mapped south into the AOI in the Registan (fig. 21–1b). Very few settlements are found in the areas 

outside the Helmand River flood plain in the Dasht-i Margo to the north and the Registan to the east and 

south. 

21C.4 Topography and Geomorphology

The topography of the Khanneshin carbonatite AOI is dominated by the bedrock outcrop of the 

Khanneshin volcano. The volcano rises to an elevation of 1,291 m above sea level (asl) (Bohannon, 

2005) and has an outcrop area of approximately 46 km2. The elevation of the base of the volcanic cone 

at the contact between the bedrock outcrop and the alluvium ranges from 950 m asl on the southwest to 

800 m asl on the northeast. The surface of the Registan desert gently slopes away from the volcanic cone 

(figs. 21C–1a, 21C–2) (Davis, 2006). The gradient to the north, from the bedrock-alluvium contact at 

the base of the Khanneshin volcano to the Helmand River, is -36 m/km (meters per kilometer). This 

gradient is representative of the gradient in all directions from the cone out to a distance of at least 6 km. 

The surface of the Registan surrounding the Khanneshin volcano is planar and is broken only by 
Chapter 21C. Geohydrologic Summary of the Khanneshin Carbonatite Area of Interest 1505

occasional hills composed of volcanic and sedimentary rock outcrops, ephemeral stream channels, and 

barchan dunes. The surface features of this area have been shaped by fluvial and eolian processes. 

Figure 21C–2. Historical streamgage locations, digitally generated drainage network, and irrigated areas in the 

Khanneshin carbonatite area of interest in southern Afghanistan.
1506 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

The upland surfaces of the Khanneshin volcano consist of weathered volcanic outcrop, 

weathered volcanic detritus, and wind-blown sediments. The Khanneshin volcano is dissected by deeply 

incised, V-shaped ephemeral stream valleys (fig. 21C–5). The major ephemeral stream valleys, inferred 

from the Digital Elevation Model- (DEM) generated drainage network (fig. 21C–2), form a dendritic 

drainage pattern. During the field visits to the AOI, the major drainages with lengths of 1 km or more 

were observed to be preferentially oriented northwest to southeast and northeast to southwest. The 

northwest to southeast orientation corresponds to the orientation of carbonatite dikes that have intruded 

through the volcanic rocks at the Khanneshin volcano (O’Leary and Whitney, 2005). The channel sides 

of the large ephemeral streams exhibit deposits of colluvium and boulders. The geomorphology of the 

drainage channels indicates that precipitation and runoff are sufficient to weather and transport 

fragments of volcanic rock. The desert plain in the AOI is composed of wind-blown sand and outcrops 

of volcanic and sedimentary rocks (fig. 21C–6). Active barchan dunes are found to the northwest, west, 

and south of the volcanic cone. 

Figure 21C–3. Photograph of vegetation on the Khanneshin volcano in the Khanneshin carbonatite area of 

interest in southern Afghanistan.
Chapter 21C. Geohydrologic Summary of the Khanneshin Carbonatite Area of Interest 1507

Figure 21C–4. Population density in the Khanneshin carbonatite area of interest and surrounding areas in 

southern Afghanistan.
1508 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

21C.5 Geohydrology

The geohydrology of Afghanistan has been described in general terms by Abdullah and 

Chmyriov (1977, book 2). As defined in their “Geology and mineral resources of Afghanistan,” the 

Khanneshin carbonatite AOI is in the Lower Helmand and Registan artesian basins of the Southern 

Afghanistan Artesian Region. The outcrops and near-surface rocks in the AOI can be grouped according 

to their physical and hydraulic properties. The generalized geohydrology of the AOI is shown in figure 

21C–4 with the underlying topography to allow examination of the geohydrology in the context of relief.

Figure 21C–7 shows the generalized geohydrology without topography for a clearer depiction of the 

geohydrologic units. Wells present in the map area (discussed in the Groundwater section) are shown in

figure 21C–8. Generalized geohydrologic groups were created from a country-wide geologic coverage 

(Doebrich and Wahl, 2006) by combining sediments and rocks into major sediment- or rock-type groups 

of similar hydrologic characteristics. The geohydrologic groups in the AOI, ranked from high to low 

relative hydraulic conductivity (Freeze and Cherry, 1979, table 2.3), are “river channel; sands, 

undifferentiated; conglomerate sediments and rocks; and intrusive rocks and lavas” (figs. 21C–7, 

21C–8). Doebrich and Wahl (2006) used geologic maps at a scale of 1:250,000, modified from Russian 

and Afghan Geological Survey (AGS) mapping, to generate the country-wide geologic coverage. The 

1:250,000-scale geologic map that cover this AOI is provided by O’Leary and Whitney (2005). 

Figure 21C–5. 

The geohydrologic groups within the AOI consist of the intrusive rocks and lavas that compose 

the bedrock outcrops of the Khanneshin volcano; the conglomerate sediments and rocks; the sands, 

undifferentiated; and the river-channel deposits. The conglomerate sediments and rocks geohydrologic 

group has the largest outcrop area. Much of these deposits, especially on the flanks of and surrounding 

Photograph of topography in the Khanneshin carbonatite area of interest in southern Afghanistan. 
Chapter 21C. Geohydrologic Summary of the Khanneshin Carbonatite Area of Interest 1509

the Khanneshin volcano, is derived from the weathering of the intrusive rocks and lavas outcrop 

(fig. 21C–7). Drenth (2009) has estimated the unconsolidated sediments to be thousands of meters thick 

over basement rocks in some basin settings of the AOI, on the basis of an interpretation of recent and 

historical aeromagnetic data. A geological sketch map and cross section in Abdullah and Chmyriov 

(1977, p. 272, fig. 4) depicts conglomerate surrounding the volcanic rocks. The conglomerate is overlain 

by unconsolidated deposits on the southwest side of the Khanneshin volcano and thick, bedded, 

caldera-type volcanic rocks on the northeast side. The unconsolidated sediments probably drain quickly 

and the presence of any shallow groundwater in the AOI is unlikely, except for possible transient zones 

of saturation that are created following precipitation and runoff events. 

Figure 21C–6. Photograph of eolian sand, sparse vegetation, and volcanic outcrops on northwest side of the 

Khanneshin volcano in the Khanneshin carbonatite area of interest in southern Afghanistan.

21C.6 Surface Water

A network of major, perennial and ephemeral streams in the Khanneshin carbonatite AOI, 

modified from AIMS (Afghanistan Information Management Services, 1997) and VMAP1 (National 

Imagery and Mapping Agency, 1995), is shown in figure 21C–2. A network representing likely 

ephemeral streams, generated with a DEM, also is shown in figure 21C–2. Names of major streams and 

identification numbers for any streamgages in the AOI also are shown in figure 21C–1b. 

The Helmand River is the only perennial surface-water body in the AOI and is likely the most 

readily available water resource. The Helmand River Basin is the largest in Afghanistan. The rivers in 

the Helmand Basin are fed by melting snow from the high mountains and precipitation from infrequent 
1510 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

storms. Great fluctuations in streamflow, from flood to drought, can be expected (Williams-Sether, 

2008). The amount of snowfall and the timing of the snow melt have large impacts on the streamflow in 

the Helmand River.

Figure 21C–7. Topography and generalized geohydrology in the Khanneshin carbonatite area of interest in 

southern Afghanistan.
Chapter 21C. Geohydrologic Summary of the Khanneshin Carbonatite Area of Interest 1511

Figure 21C–8. Geohydrology, mapped faults, and well locations in the Khanneshin carbonatite area of interest in 

southern Afghanistan.

The drainage area at the Helmand River streamgage station at Malakan (Afghanistan 

identification number 4-0.000-4M, figs. 21C–1b, 21C–2) is 132,880 km2, about 17,400 km2 of which

drains to noncontributing (closed) basins. The Malakan streamgage station is located about 16 km west 
1512 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

of the base of the Khanneshin volcano (table 21C–2). Streamflow in the Helmand River was gaged by 

Afghanistan ministries from 1970 to 1978, and mean annual flow for that period was 157 m3/s (cubic 

meters per second) with a standard deviation of 97 m3

/s (Williams-Sether, 2008). The highest maximum

monthly mean streamflow was 1,270 m3/s, in April 1976, and the lowest minimum monthly mean 

streamflow was 13.6 m3/s, in October 1972. The timing and volume of flow in the Helmand River are

dependent on reservoir releases and the characteristics of the snowpack in the upper elevations of the 

headwaters (Favre and Kamal, 2004a). Flows are influenced by water releases from the Kajakai Dam, 

which is about 250 km upstream from the streamgage station at Malakhan. A streamgage station was 

re-established at the site of the historical station at Malakan in 2008; however, data from this station 

were not available at the time of this investigation. Statistical summaries of streamflow data for all 

available historical gages in Afghanistan can be accessed at http://afghanistan.cr.usgs.gov/water.php.

The Helmand River is the only major perennial river in western Asia between the TigrisEuphrates and Indus Rivers (Whitney, 2006) and, as a result of the sparse precipitation in this part of 

Afghanistan, is the source of nearly all water resources in the local area. The river supplies water to

irrigation canals in nearby villages, and likely recharges shallow groundwater through infiltration into 

coarse-grained river-channel deposits near the river (fig. 21C–9). The calculated seasonal 7-day low 

flows with a 2-year recurrence interval varied only slightly, approximately from 51 to 66 m3/s, 

throughout most of the year (June through February), and increased to 91 m3

/s during March through 

May (Williams-Sether, 2008). 

Table 21C–2. Statistical summary of monthly and annual mean streamflows for the Helmand River at Malakan 

streamgage station. 3 [m /s, cubic meters per second]

4- 0.000-4M HELMAND RIVER AT MALAKAN

Maximum Minimum Mean

Standard Percentage Month Streamflow Water year of Streamflow Water year of Streamflow Coefficient of deviation of annual (m3/s) occurrence (m3/s) occurrence (m3/s) variation 3 (m /s) streamflow

October 130 1977 13.6 1972 75.0 45.6 0.61 4.13

November 142 1977 34.3 1972 77.6 38.6 0.50 4.27

December 129 1977 30.8 1972 86.6 30.3 0.35 4.77

January 174 1977 65.4 1971 120 32.4 0.27 6.62

February 226 1970 46.1 1971 147 60.2 0.41 8.08

March 576 1976 24.3 1971 199 165 0.83 11.0

April 1,270 1976 41.6 1971 333 378 1.13 18.4

May 1,200 1976 53.5 1971 394 368 0.93 21.7

June 357 1976 20.7 1971 148 110 0.74 8.16

July 175 1976 15.5 1971 90.9 54.9 0.60 5.01

August 133 1972 16.0 1971 75.0 44.5 0.59 4.14

September 124 1972 14.8 1971 68.5 40.6 0.59 3.78

Annual 364 1976 35.4 1971 157 97.1 0.62 100
Chapter 21C. Geohydrologic Summary of the Khanneshin Carbonatite Area of Interest 1513

Figure 21C–9. Aerial view of the Helmand River on 21 September, 2009, showing cultivated fields and irrigation 

canals in the Khanneshin carbonatite area of interest in southern Afghanistan.

With the exception of the Helmand River, there is no evidence of perennial surface water in the 

AOI. No springs were mapped in the AOI in the VMAP1 database (National Imagery and Mapping 

Agency, 1995) (fig. 21C–2). There is evidence of surface-water flow at the Khanneshin volcano, which 

is likely the result of short-duration rainfall events. Evidence of these types of flow events was observed 

on 16 August, 2010, during a field visit to an ephemeral stream on the north side of the Khanneshin 

volcano. Recent flow in the drainage was indicated by features that typically result from a substantial 

precipitation and runoff event. Signs of flow included mud cracks on surfaces surrounding plunge pools, 

pot holes, and low-gradient areas where standing water and sediments accumulated; ripple marks in 

sediments in these same areas; and bedrock-outcrop surfaces in high-gradient areas (shoots and troughs) 

with no sediment accumulations, indicating that the surfaces had been washed clean of any sediments. 

These fluvial features could not have persisted long in the windy environment of the Khanneshin 

volcano. The flow that produced these features probably occurred within a month of the field visit, and 

could have been contemporaneous with monsoonal precipitation that can occur in this part of 

Afghanistan. The vegetation in this wash was actively growing and there were signs of recent animal 

activity in the drainage.

21C.7 Groundwater

Although few data exist from which to quantify this resource, groundwater is likely present near 

the Khanneshin volcano and in thick, unconsolidated to semi-consolidated basin-fill sediments 
1514 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

consisting of silt, sand, and gravel in the Khanneshin carbonatite AOI. The basin-fill material may be 

thousands of meters thick in places (Drenth, 2009). The water level is likely to be near the land surface 

in the river channel adjacent to the Helmand River and the groundwater is accessed by dug wells. Away 

from the Helmand River the aquifer is known to be deeper, tens to hundreds of meters deep. Given the 

characteristics of the region and the age of the VMAP1 database (National Imagery and Mapping 

Agency, 1995), the wells mapped by VMAP1, shown in figure 21C-8, are likely to be shallow dug wells 

that access water in a shallow aquifer that is isolated from the deeper aquifer. Deep water-supply wells 

have been drilled in the AOI and surrounding area by the U.S. government (wells numbered 34, 126, 

and 158, fig. 21C–8). The wells were drilled to depths of approximately 450 m bgs and the information 

available indicates that hydraulic characteristics vary considerably between wells. Well 126 is described 

as encountering all clay, and therefore had no appreciable yield, whereas well 158 had a yield of more 

than 10 L/s (liters per second). Well 34 is described as artesian, with a potentiometric surface more than 

3 m above land surface. 

Very few community supply wells were found in well databases at the time of the study 

(fig. 21C–8). Shallow drilled and dug water wells are probably present in the more densely populated 

areas along the Helmand River (fig. 21C–4). River-channel sediments in the Kabul Basin were found to 

have hydraulic conductivities of tens of meters per day (Mack and others, 2010). Where coarse-grained 

river-channel sediments are present adjacent to the Helmand River (fig. 21C–7), there is the potential for 

considerable infiltration of river water to a properly constructed supply well. Surface water in areas of 

high water use may contain agricultural contaminants and other wastes; therefore, the quality of the 

infiltrated water would need to be assessed. Groundwater withdrawals near rivers would need to be 

closely monitored to avoid adverse effects on streamflow and on existing surface-water uses.

A hydrologic reconnaissance study was conducted from 20 to 22 September, 2010, near 

Khanneshin village located along the Helmand River (fig. 21C–1a,b). Well locations were determined 

and depths to water were measured. The access to well sites was limited to a walled compound at the 

Khanneshin village about 1.5 km from the active channel of the Helmand River. The compound had 

been a local government facility, with some small-scale farming, and contained several hand-dug and 

tube wells. Water levels in the wells were about 4 m bgs (about 633 m asl). Well users indicated that the 

wells could be pumped for extended periods with no noticeable decrease in discharge. The drilling of a 

water-supply well with a planned total depth of about 450 m bgs was attempted. Drilling problems 

resulted in cessation of well drilling at a depth of about 410 m bgs. With the exception of the uppermost 

shallow aquifer, no water was encountered during drilling. 

Groundwater in the AOI probably occurs in shallow zones of saturation resulting from local 

recharge from the Helmand River. Shallow aquifers may also be found where large ephemeral streams 

originating on the Khanneshin volcano discharge onto the surrounding desert floor. Perched water could 

occur here, particularly where porous alluvium overlies less permeable alluvium and bedrock. In “The 

watershed atlas of Afghanistan, Part IV, Description of watersheds,” Favre and Kamal (2004b) provide 

the following description: “The water flows from a multitude of seasonal streams back into the Helmand 

River on each side of the Khanishin Gar volcano.” The reference to seasonal streams supports the 

concept that ephemeral streams discharging water from the Khanneshin volcano onto the Registan may 

result in zones of saturation at the discharge areas.

The deeper aquifers, more than 100 m deep and currently (2011) accessed by a few water-supply 

wells, probably receive recharge from outside the AOI, perhaps even as far as hundreds of kilometers to 

the north in the Hindu Kush Mountains. Another potential recharge area is to the south in the hills that 

straddle the Afghanistan and Pakistan border. Groundwater in deep aquifers is likely to be thousands of 

years old. The quality of water in these deep aquifers is unknown; this water likely has a long residence 

time and could be saline or contain high concentrations of other ions. Groundwater studies, including 

chemical and isotopic analysis, would be needed to adequately characterize the groundwater in the 

deeper aquifers in the AOI. 
Chapter 21C. Geohydrologic Summary of the Khanneshin Carbonatite Area of Interest 1515

21C.8 Lineament Analyses

Lineaments are photolinear features that could be the result of underlying zones of high-angle 

bedrock fractures, fracture zones, faults, or bedding-plane weaknesses. Lineament analyses of the 

Khanneshin carbonatite AOI (B.E. Hubbard, T.J. Mack, and A.L. Thompson, unpub. data, 2011) were 

conducted using DEM and natural-color satellite imagery (fig. 21C–10) and Advanced Spaceborne 

Thermal Emission and Reflection Radiometer (ASTER) satellite imagery (figs. 21C–11a,b). Lineament 

identification and analysis have long been used as a reconnaissance tool for identifying areas in 

carbonate bedrock environments where groundwater resources are likely to be found (Lattman and 

Parizek, 1964; Siddiqui and Parizek, 1971). Lineament analysis is increasingly used to identify areas of 

high relative well yields in other bedrock settings, including crystalline bedrock (Mabee, 1999; Moore 

and others, 2002). The lineaments shown in figure 21C–10 were delineated visually, whereas those in 

figure 21C–11 were delineated using an automated process and on the basis of the multispectral 

characteristics of the land surface (B.E. Hubbard, T.J. Mack, and A.L. Thompson, unpub. data, 2011). 

Water wells in bedrock aquifers are most productive where boreholes are located in areas of highly 

fractured bedrock. Areas where lineament density is high (figs. 21C–10, 21C–11a, and 21C–11b) 

potentially are areas where bedrock fractures are more prevalent than in other areas of the AOI.

Lineaments provide an indication of areas that warrant further investigation for optimal bedrock 

water-well placement. Lineaments may also indicate areas of preferential flow and storage of 

groundwater, and areas with a high density of lineaments may indicate high secondary porosity. Any 

lineament analyses, including those presented in this investigation, need to be corroborated by field 

investigations and additional data to confirm the nature of the lineaments and their relation to waterfilled bedrock fracture zones. 

The DEM and natural-color satellite imagery lineaments analysis in the AOI was limited to the 

Khanneshin Volcano subarea based on areas of mapped bedrock. The ASTER lineament analysis 

included a larger area and limited automated topographic surface analyses (B.E. Hubbard, T.J. Mack, 

and A.L. Thompson, unpub. data, 2011). However, an orthogonal network of north-northwest- and eastnortheast-trending lineaments is present that indicates a likely pervasive fracture pattern. Where these 

patterns intersect, there may be areas of potentially increased transmissivity and secondary porosity. 

Some of the ASTER lineaments coincide with the DEM lineaments and others follow features near the 

Helmand River that are likely to be related to irrigation networks. The nature of other ASTER patterns is 

not clear and their interpretation would require comparison with additional data. 
1516 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 21C–10. Lineaments and lineament density based on 30-meter digital-elevation-model data and 

natural-color Landsat imagery in the Khanneshin carbonatite area of interest in southern Afghanistan.
Chapter 21C. Geohydrologic Summary of the Khanneshin Carbonatite Area of Interest 1517

a 
1518 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

b 

Figure 21C–11. (a) Lineaments and lineament density based on 30-meter multispectral Landsat imagery and 

(b) lineaments and lineament density based on 15-meter multispectral Landsat imagery in the Khanneshin 

carbonatite area of interest in southern Afghanistan.
Chapter 21C. Geohydrologic Summary of the Khanneshin Carbonatite Area of Interest 1519

21C.9 Summary and Conclusions

The Helmand River is the most readily available source of water in or near the Khanneshin 

carbonatite area of interest (AOI). It is used for irrigation and is likely to be the primary source of 

recharge to shallow alluvial aquifers adjacent to the river. Close monitoring and careful management of 

large withdrawals from the Helmand River to support mining or other activities in the AOI would help 

to avoid adverse impacts on local water uses. The flow of water in the Helmand River varies seasonally, 

with peak flow usually occurring in the spring and early summer and low flow typically occurring from 

late summer through winter. Renewed streamflow monitoring and determination of the characteristics of 

flow would be needed to assess whether, when, and how much water could be diverted for use. The total 

amount of water available in the Helmand River system depends on snowfall in the Hindu Kush 

Mountains. The amount of measured and estimated snow in the mountains can be used to predict 

whether the runoff and streamflow will be above average, normal, or below average.

Ephemeral runoff from the Khanneshin volcano most likely recharges local shallow perched 

aquifers; however, this resource is likely to be limited and may be fully utilized. Recharge to deeper 

aquifers in and near the AOI probably is derived from distant rather than local sources. Deep 

groundwater resources are also likely to be thousands of years old. A program of chemical and isotopic 

analysis would help to assess the characteristics and sustainability of this resource. The production of 

water from deeper aquifers may support new uses; however, overuse of the water resources in a desert 

environment can easily result in adverse effects. The quality of water in deep aquifers is unknown at this 

time. It is possible that water in deeper aquifers has a long residence time and is saline or contains high 

concentrations of other ions. Field investigations including geophysical surveys, borehole hydraulic 

testing, and analysis of water quality would be needed to adequately characterize the availability and 

quality of groundwater in the AOI.

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