Drainage Basin Shape Indices to Understanding Channel Hydraulics

Sound‐Side Inundation and Seaward Erosion of a Barrier Island During Hurricane Landfall

“…Finally, we calculated several morphometric indices to evaluate the apparent similarities in the shapes of outwash and overwash features. These included the circularity ratio C r = 4 πA / P 2 (Jones et al., 2012; Das et al., 2022, their Equation 12), which is the ratio of feature area to the area of a circle with the same perimeter; a second, somewhat related ratio R 2 = A / A c , where A c is the area of the convex hull enclosing the feature area; the distortion index DI = P /[( π + 2)(2 A / π ) 0.5 ] proposed by Lazarus et al. (2021, their Equations 1 and 2), which is the ratio of the measured perimeter of a feature to the perimeter of a semicircle with the same area; and the indenture index I = 0.5 PL /( A + L 2 ) (Das et al., 2022, their Equation 25), which relates the measured perimeter to the perimeter of a rectangle with the same A and same L .…”

“…Finally, we calculated several morphometric indices to evaluate the apparent similarities in the shapes of outwash and overwash features. These included the circularity ratio C r = 4πA/P 2 (Jones et al, 2012;Das et al, 2022, their Equation 12), which is the ratio of feature area to the area of a circle with the same perimeter; a second, somewhat related ratio R 2 = A/A c , where A c is the area of the convex hull enclosing the feature area; the distortion index DI = P/[(π + 2)(2A/π) 0.5 ] proposed by Lazarus et al (2021, their Equations 1 and 2), which is the ratio of the measured perimeter of a feature to the perimeter of a semicircle with the same area; and the indenture index I = 0.5PL/(A + L 2 ) (Das et al, 2022, their Equation 25), which relates the measured perimeter to the perimeter The beige and pink bars highlight areas that deviate from the general trend; area 1 is near the center of the island where fewer washout channels formed and area 2 is at the northeast end of the island, where the most severe erosion occurred (see Figures 4 and 6), and where it was difficult to identify shorelines. of a rectangle with the same A and same L. All these indices indicate the complexity of the boundary of a given area and displayed similar abilities to discriminate among the various shapes, so we chose to use DI (Figure 8e) because it relates to a common depositional fan shape (Lazarus et al, 2021 and citations therein).…”

Morphometric analysis of Halda River basin, Bangladesh, using GIS and remote sensing techniques

“…The ratio between basin length and width is 1.63. Lemnisctae's ratio, basin length and width indicate that the lower order streams with shorter distances carry the sign of circularity whereas the longer order streams produce the elongated nature of the drainage basin [ 10 , 53 , 111 , 112 ].…”

Parámetros de forma de una cuenca referenciados con el círculo y la lemniscata, aplicados a la subcuenca del río Llanganuco – Perú.

“…Las inundaciones causan da ños a los recursos naturales y a la calidad del medio ambiente, en consecuencia, aumenta la vulnerabilidad de los sistemas, tanto naturales como humanos (Tran et al ,2010;Ogarekpe et al , 2020). Seg ún Das et al (2022) los parámetros que miden la forma de la cuenca de drenaje son de gran importancia porque no solo miden las formas de las cuencas, sino que también brindan informaci ón cuantitativa sobre la forma de la cuenca que controla el hidrograma de flujo del canal. Asimismo, la forma de la cuenca influye en el comportamiento hidrol ógico de las máximas avenidas de una cuenca.…”