Arshad Ashraf

Glacial lake outburst flood hazards in Hindukush, Karakoram and Himalayan Ranges of Pakistan: implications and risk analysis

One of the spectacular effects of recent atmospheric warming in the Himalayan region has been the creation of meltwater lakes on the lower sections of many glaciers. Climate change is likely to exacerbate further some of these natural hazards such as glacial lake outburst floods (GLOFs), which can cause major social and economic damage for large populations living in the Himalayan region. Thirty-five destructive outburst floods have been recorded for the Karakoram Range in the past 200 years. Systematic application of remote sensing and geographic information systems (GIS) has revealed the formation of about 2420 glacial lakes in the Hindukush-Karakoram-Himalaya (HKH) Region of Pakistan, among which 52 lakes are characterized as potentially dangerous GLOF hazards. About 62% of the GLOF lakes belong to End Moraine Dammed type and 25%to Cirque type. Due to poor livelihood conditions, lack of resources and proper management within the system the local communities have a problem intaking effective response measures for risk reduction or mitigation. There is aneed to create awareness of flood hazard, coordination and capacity buildings for preparedness and risk reduction among target communities. High resolutionsatellite data integrated with ground information can be utilized effectively for regular monitoring of these lakes in order to mitigate flood risk hazard in future.

Hydrological response to environment change in Himalayan watersheds: Assessment from integrated modeling approach

Land use changes such as deforestation, increase in cropping or grazing areas and built-up land, likely modify the water balance and land surface behavior in the Himalayan watersheds. An integrated approach of hydrological and hydraulic modeling was adopted for comparative analysis of hydrological pattern in three Himalayan watersheds i.e. Khanpur, Rawal and Simly situated in the Northern territory of Pakistan. The rainfall-runoff model SWAT- Soil and water assessment tool and HydroCAD were calibrated for the selected watersheds. The correlation analysis of the precipitation data of two climate stations i.e. Murree and Islamabad, with the discharge data of three rivers was utilized to select best suitable input precipitation data for HydroCAD rainfall-runoff modeling. The peak flood hydrograph were generated using HydroCAD runoff to optimize the basin parameters like CN, runoff volume, peak flows of the three watersheds. The hydrological response of the Rawal watershed was studied as a case study to different scenarios of land use change using SWAT model. The scenario of high deforestation indicated a decline of about 6.3% in the groundwater recharge to stream while increase of 7.1% in the surface runoff has been observed under the scenario of growth in urbanization in the recent decades. The integrated modeling approach proved helpful in investigating the hydrological behavior under changing environment at watershed level in the Himalayan region.

Integration of Groundwater Flow Modeling and GIS

The development of a sufficient understanding on which to base decisions or make predictions often requires consideration of a multitude of data of different types and with varying levels of uncertainty. The data for the development of numerical groundwater flow model includes time-constant parameters and time-variant parameters. The time-constant parameters were mainly extracted from thematic data layers generated from GIS and image processing of remote sensing data. Integrated approaches in GIS play a rapidly increasing role in the field of hydrology and water resources development. It provides suitable alternatives for efficient management of large and complex databases developed in different model environments. Remote sensing (RS) technology is capable of providing base for quantitative analysis of an environmental process with some degree of accuracy. It provides an economic and efficient tool for landcover mapping and has its advantages in planning and management of water resources (Ashraf and Ahmad 2008 & Ahmad et al., 2011). One of the greatest advantages of using remote sensing data for hydrological investigations and monitoring is its ability to generate information in spatial and temporal domain. Though, the presence of groundwater cannot be directly ascertained from RS surveys, however, satellite data (GRACEGravity Recovery and Climate Experiment and GOCE-Gravity field and steady-state Ocean Circulation Explorer) provides quick and useful baseline information on the parameters that control the occurrence and movement of groundwater such as geomorphology, direction of groundwater flows, lineaments, soils, landcover/landuse and hydrology etc.

Heterogeneous expansion of end-moraine dammed lakes in the Hindukush-Karakoram-Himalaya ranges of Pakistan during 2001–2013

Global climate change during the twentieth century had a significant impact on the glaciers that resulted in creation of new lakes and expansion of existing ones, and ultimately an increase in the number of glacial lake outburst floods (GLOFs) in the Himalayan region. This study reports variation of the end-moraine dammed lakes in the high altitude Hindukush-Karakoram-Himalaya (HKH) region of Pakistan to evaluate future floods hazard under changing climate in this region. An integrated temporal remote sensing and Geographic information system (GIS) based approach using satellite images of Landsat-7 and 8 was adopted to detect 482 endmoraine dammed lakes out of which 339 lakes (>0.02 km2) were selected for temporal change analysis during the 2001-2013 period. The findings of the study revealed a net expansion in the end-moraine dammed lakes area in the Karakoram (about 7.7%) and in the Himalayas (4.6%), while there was a net shrinkage of about 1.5% in the lakes area in the Hindukush range during this period. The percentage increase in the lakes’ area was highest above 4500 m asl in the Hindukush, within 3500-4000 m asl in the Himalayas and below 3500 m asl in the Karakoram range. The overall positive change in the lakes’ area appears to prevail in various altitudinal ranges of the region. The heterogeneous areal changes in the endmoraine dammed lakes might be attributed to different climate regimes and glacial hydrodynamics in the three HKH ranges. A periodic monitoring of the glacial lakes and their associated glaciers is essential for developing effective hazard assessment and risk reduction strategies for this high altitude Himalayan region.

Monitoring Groundwater Flow Dynamics and Vulnerability to Climate Change in Chaj Doab, Indus Basin, Through Modeling Approach

The growing trend in global warming has impacted the hydrological system of the Indus River system. The variations in climate have influenced not only the local but also the regional behavior of groundwater system in the Indus River basin. It would also be crucial to investigate characteristics and behavior of this resource in order to ensure safe yield for irrigation, industry, and sustaining livelihood of millions of people of Indus area. A good knowledge of the problem and analysis of various components of the hydrological system are thus essential to achieve optimum groundwater management goals for sustaining agriculture development. The numerical groundwater flow model—Feflow—was calibrated to simulate groundwater flow behavior in upper Chaj Doab, Indus basin, during 1985–2005. The model had predicted an average decline of about 0.96 m in groundwater levels during the calibrated period and further reduction up to year 2020. A major breakthrough of groundwater depletion was observed in year 1999 when the last drought prevailed for over 3–4 years in this region. Major causative factors of watertable decline may include decrease in surface water for groundwater recharge, variability and change in rainfall pattern, and overexploitation of groundwater. The situation has resulted not only in exaggerating the cost of groundwater pumping, but also in abandoning existing wells. The integration of groundwater flow modeling and geoinformatic techniques proved helpful in analyzing the resource situation as well as vulnerability of the groundwater system to influential factors like climate change. As the country is already water stressed and predicted to face water scarcity in future, there is a need to monitor the groundwater system periodically on long-term basis to cope with food and water security issues in the Indus basin in future.

Appraisal of Groundwater Flow Simulation in the Sub- Himalayan Watershed of Pakistan

Numerical modeling of an aquifer is increasingly used as a power tool for monitoring and management of groundwater. This paper focuses on conceptualizing hydrogeo‐ logical condition and establishing numerical simulation model using Visual MOD‐ FLOW to simulate the continuous depletion of groundwater in the southwestern part of the Soan watershed in Pakistan. An integrated groundwater modeling and manage‐ ment approach was adopted to provide suitable alternatives for water management in different hydro-environments. Geospatial techniques were employed for spatial database development, integration with a remote sensing (RS), and numerical groundwater flow modeling capabilities to simulate groundwater flow behavior. The calibration results indicated a reasonable agreement between the calculated and observed heads. The calibrated heads were used as initial conditions in the transientstate modeling. The modeling approach facilitated in identifying potential groundwa‐ ter regime besides providing artificial recharge options for sustainable groundwater development.

Groundwater and Contaminant Hydrology

Contaminant hydrology is the study of processes that affect both ground and surface water pollution. It draws on the principles of hydrology and chemistry. Contaminant hydrology and water quality research seeks to understand the role of soil properties and hydrologic processes on ground and surface water pollution and develop strategies to mitigate their impacts. Research is done at all scales varying from soil pore to basin scale and covers both traditional and emerging contaminants. Groundwater and contaminant hydrology studies include fate and transport of jet fuel leakages from oil depots, producing water injection in shallow wells from the oil and gas exploration field concession areas, veterinary pharmaceuticals from landapplied manure, pathogen losses from manure application, fate and transport of disposal wastes in unlined evaporation ponds from pharmaceutical industries, impacts of tile drainage on sediment and nutrient pollution on Rivers, sediment-turbidity relationships, water quality modeling, and TMDL and paired watershed studies.