A remote sensing contribution to hydrologic modelling in arid and inaccessible watersheds, Pishin Lora basin, Pakistan

Abstract

Abstract:The lack of adequate field measurements often hampers the construction and calibration of rainfall-runoff models over many of the world's watersheds. We adopted methodologies that rely heavily on readily available remote sensing datasets as viable alternatives for assessing, managing, and modelling of such remote and inadequately gauged regions. The Soil and Water Assessment Tool was selected for continuous (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) rainfall-runoff modelling of one such area, the northeast part of the Pishin Lora basin (NEPL). Input to the model included satellite-based Tropical Rainfall Measuring Mission precipitation data, and modelled runoff was calibrated against satellite-based observations, the latter included: (i) monthly estimates of the water volumes impounded by the Khushdil Khan (latitude 30°40 0 N, longitude 67°40 0 E), and the Kara Lora (latitude 30°34 0 N, longitude 66°52 0 E) reservoirs, and (ii) inferred wet versus dry conditions in streams across the NEPL. Calibrations were also conducted against observed flow reported from the Burj Aziz Khan station at the NEPL outlet (latitude 30°20 0 N; longitude 66°35 0 E). Model simulations indicate that (i) average annual precipitation (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005), runoff and recharge in the NEPL are 1300 ð 10 6 m 3 , 148 ð 10 6 m 3 , and 361 ð 10 6 m 3 , respectively; (ii) within the NEPL watershed, precipitation and runoff are high for the northeast (precipitation: 194 mm/year; runoff: 38 ð 10 6 m 3 /year) and northwest (134 mm/year; 26 ð 10 6 m 3 /year) basins compared to the southern basin (124 mm/year; 8 ð 10 6 m 3 /year); and (3) construction of delay action dams in the northeast and northwest basins could increase recharge from 361 ð 10 6 m 3 /year up to 432 ð 10 6 m 3 /year and achieve sustainable extraction. The adopted methodologies are not a substitute for traditional approaches, but they could provide first-order estimates for rainfall, runoff, and recharge in the arid and semi-arid parts of the world that are inaccessible and/or lack adequate coverage with field data.

Study of Subsidence and Earthquake Swarms in the Western Pakistan

“…Seismic reflection profile 1 shows the depth to the bedrock (red-colored horizon), which is estimated to begin at a depth of ~380 m ( Figure 5). A previous study showed that the bedrock is attributable to the Shrinab Formation, which has numerous reflectors that could be explained by alternating limestone and shale [20]. At the point where it intersects with profile 2, seismic profile 1 reveals a rising of the bedrock, which suggests complex folding in the bedrock affecting overlaying Quaternary alluvial deposits.…”

“…The dominant alluvial aquifers, which have an average thickness of ~300 m and a porosity of ~10%, are adjacent to the major mountain ranges: the Chiltan and Murdar Ranges [2]. The consolidated deposits of limestone, sandstone, and conglomerates are highly fractured, making aquifers, which are largely found in the Chiltan Formation and Shrinab Formation [20,21]. The Shrinab Formation is a deep aquifer composed of thick-bedded limestone with occasional shale and marl layers.…”

“…Profile 3 clearly shows the presence of a large asymmetric Quaternary basin up to ~500 m deep. Following the results of previous studies [20] and adding our new interpretations from the seismic data, a geological model along seismic profile 3 has been generated ( Figure 7). The eastern part of profile 3 reveals what appears to be a thrust fault serving as the boundary between the Shrinab and the Chiltan Formations.…”

“…On an ascending path, the ALOS-1 Figure 7. Schematic cross-section AA' (parallel with seismic profile 3) modified from a previous study [20] to explain subsidence in the Quetta Valley and surrounding areas. The Bouguer anomaly profile of AA' shows highs and lows forming a trend likely related to mountain ranges and basins.…”

Essentials of Endorheic Basins and Lakes: A Review in the Context of Current and Future Water Resource Management and Mitigation Activities in Central Asia

“…It receives water from the Helmand River that originates in the Hindu Kush Mountains [31,32]. The basin is sometimes divided into three parts: an upper delta of the Helmand River; a lower delta, which is comprised of wetlands with the lowest part ending in a hypersaline lake named Gowd-e-Zareh (Gaud-i Zirreh) [31]; and finally a number of small endorheic sub-basins such as the Pishin Lora basin, which ends in the hypersaline terminal Hamun-Lora Lake on the border of Afghanistan and Pakistan [33]. The Sistan basin has very low precipitation, and its water Among the Central Asian River basins, only the Ob river and its tributaries drain into the Arctic Ocean, whereas all other areas have internal drainage [22].…”