Erratum In the expanded summary of the article, “Hydrological Modeling and Characterization of the Khanpur Watershed, Pakistan,” by Muhammad Zaheer, Zulfiqar Ahmad, and Asfandyar Shahab, that appeared in the May 2016 issue of Journal AWWA (Vol. 108 No. 4 p.76), there were errors in Table 1, and Asfandyar Shahab’s name appeared incorrectly in the byline at the top of the page. These errors were corrected before publication of the full-text version of the manuscript, which was published online in May. Additionally, the corrected table is printed here. It should be noted that Table 1 from the expanded summary is the same table as Table 4 in the full-text version of the manuscript.
TABLE 1
Physical characteristics of the Khanpur watershed Variable
Area—km2
797
Perimeter—km
232
Watershed length—km
54
Stream order
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5
Bifurcation ratio
3.5
Stream density—no./km2
0.5
Drainage density—km/km2
0.7
Largest stream—km
64
Circularity ratio
0.6
Compactness factor
1.2
Lemniscate ratio
2.8
Elongation ratio
0.6
Form factor
0.27
Shape factor (Horton 1932)
3.7
Basin slope
0.04
2016 © American Water Works Association
78
Measure
Expanded Summary
Hydrological Modeling and Characterization of the Khanpur Watershed, Pakistan MUHAMMAD ZAH E E R, ZU L F IQ A R A H M A D, A N D AS FAN D YAR S H AH AB http://dx.doi.org/10.5942/jawwa.2016.108.0043
Hydrological methods are notably influenced by climatic changes such as precipitation, temperature variation, and human activities. A good understanding and assessment of watershed hydrologic progression is of great importance for predicting flood potential and to mitigate flood vulnerability, and has become a crucial issue for management, planning, and sustainable development of a watershed. The response of a particular watershed to different hydrological processes and its resulting behavior depend on various hydrological and geomorphological parameters. In the current study, the impact of precipitation was analyzed on the surface flows of the Haro River at the Khanpur watershed of Pakistan. The Khanpur watershed is one of the largest watersheds in Pakistan, with its main water channel and high spatial changeability of precipitation attributable to extremely undulating surface topography and complex interaction between the land elevation and precipitation. This study, combined with a rainfall-runoff modeling software, aimed to determine the peak discharge of the
TABLE 1
Physical characteristics of the Khanpur watershed Variable
Measure
Area—km2
797
Perimeter—km
232
Watershed length—km
54
Stream order
5
Bifurcation ratio
3.5
Stream density—no./km2
0.5
Drainage density—km/km2
0.7
Largest stream—km
64
Circularity ratio
0.19
Compactness factor
1.2
Lemniscate ratio
2.8
Haro River. A correlation analysis was used to select input precipitation data. The Khanpur watershed hydrograph was generated using inflow data from the Khanpur Dam and precipitation data for 1991–2010. Morphological characteristics obtained by Horton’s method revealed a dendritic pattern of streams within the watershed and that the Khanpur watershed is underlain by impermeable material. Strahler’s method proved that the Khanpur watershed is a fifth-order stream system and was used in calculating shape factors (elongation ratio, form factor, and compactness factor). Table 1 shows that the watershed is less elongated and its maximum symmetry is that of a circle, square, or cube. With the analysis of watershed characteristics, we were able to estimate runoff volume and flood fluctuation. In the relative hydrological approach, large amounts of data were used to study the parallels and changes in different places and to interpret all of these variables in terms of underlying climate change parameters. Identifying the frequency of a specific rainfall depth or duration that is developed from a statistical analysis of historical rainfall data does not mean that the characteristics of a future storm event can be accurately predicted. However, it is because of these same assumptions and uncertainties that strict adherence to an acceptable methodology is justified. The future planning for water resources ought to take into account a probable environmental change scenario that includes both sensitivities to change and recent changeability over time. A complete evaluation of morphometric parameters and their control and influence on the rainfall-runoff relation and behavior of streamflow is mandatory for characterization and management of a watershed. Corresponding author: Muhammed Zaheer is a doctoral student at the China University of Geosciences, Lumo Rd., POB 430074, Wuhan, Hubei, China 430074;
[email protected].
Elongation ratio
1.8
Form factor
0.27
REFERENCE
Shape factor (Horton 1932)
3.7
Basin slope
0.04
Horton, R.E., 1932. Drainage-Basin Characteristics. Eos, Transactions American Geophysical Union, 13:1:350. http://dx.doi.org/10.1029/ TR013i001p00350.
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