Status of wildlife between Kota barrage and Jawahar Sagar Dam, Rajasthan

Abstract

The present study examined the impacts of post-construction phase of the cable-stayed bridge on the aquatic wildlife and river habitat quality of the Chambal River between Kota barrage and Jawahar Sagar dam, Rajasthan. The study was carried out between March and November 2021. The study area was divided into 5 segments (each comprising 5 Km length of river) and the segment 1 stats from the Kota barrage. We recorded good signs/ activities of smooth-coated otters in the study area. This species is listed under “Schedule II” of IWPA 1972 and "Vulnerable" as per the IUCN Red List. A total of 10 sites within five river segments were surveyed for otter signs during pre-monsoon and post-monsoon seasons. Out of which five sites (50%) have shown positive otter signs (fresh spraints, tracks, and direct sightings) during pre-monsoon, whereas in the post-monsoon season the number of otters occupied sites have reduced to four sites (40%). The otter occupancy map indicated, the segment 2 (just above the bridge area) had high level of otter presence. We recorded good population of bird diversity between Kota barrage and Jawahar sagar dam. A total of 132 bird species, which includes 45 wetland birds (N=1569), 21 species of raptors (N=928), and 66 species of other terrestrial birds (N=1351) were recorded. These include two Critically Endangered (Indian Vulture and Red-headed Vulture), one Endangered (Egyptian Vulture), one Vulnerable (Woolly-necked Stork) and four Near Threatened species (River Tern, Black-headed Ibis, Oriental Darter and Alexandrian parakeet). During the study period, the raptors, Indian Vulture (Gyps indicus) and Egyptian vultures (Neophron percnopterus) were very commonly recorded and more number of nests were recorded in the third segment of the study stretch. In addition to vulture nests, we also observed nests of Bonelli's eagle (Aquila fasciata) and Dusky eagle-owl (Bubo coromandus) in the riverside escarpments. We also recorded nests of three waterbird species, which include Grey Heron (Ardea cinerea), Black-crowned night heron (Nycticorax nycticorax) and Woolly necked stork (Ciconia episcopus). Avian richness was varying with the season maximum number of waterbirds were observed during pre-monsoon (S=40), this same trend was followed by raptors (S=15) and other terrestrial birds (S=57). The bird occupancy map indicated that the segment 1 and segment 2 supported high abundance birds. We also recorded two species of aquatic reptiles, which are Mugger (Crocodylus palustris) and Indian roofed turtle (Pangshura tecta). Though, the river banks are mostly of rocky and large boulders with limited sand beach, we found quite a few nesting sites of muggers along the river banks. A total of 34 individuals and 23 individuals of muggers were recorded during pre-monsoon and post-monsoon respectively. The study area also supports good population of freshwater fishes. Rapid Assessment Report - 6 - During the study we recorded 46 species of fishes from the study area. Fishes belonging to the carp family were dominant in species richness (S=22). Among the 46 species of fish, three species are listed under threatened categories as per the IUCN Red List. During the study period the important physicochemical parameters of the water was monitored and the values were significantly varied between the river segments (p<0.05). The pH was found to be slightly alkaline across the river segments ranged from 7.08±0.02 and 8.55±0.01. Like conductivity, total dissolved solids in water (TDS) varied, ranging from 91.54 ppm at the second segment of the river in postmonsoon to 150 ppm at the second segment in pre-monsoon. All water quality parameters were found within the normal range of river water quality. Based on our findings we conclude that the cable-stayed hanging bridge of Kota does not have any negative impact on the wildlife of the Chambal River. The bridge is on the stable rocky gorge area, around 30 m above the water level across the river Chambal without any supporting billers from the riverbed. Thus, there is no direct contact between the river and bridge structure. Further, the technology used in this structure is marvellous, because it is totally vibration and notice proof. In this study we had some significant observations very close to this cable bridge such as an active nest of Egyptian Vulture (Neophron percnopterus) very close to this bridge (25° 8'23.14"N, 75°47'36.64"E), which is just 80 meters away from the bridge and a nest of Woolly-necked Stork (Ciconia episcopus) just 200 meters downstream from the bridge (25° 8'20.90"N, 75°47'33.11"E). Generally, Woolly-necked Storks are assumed to prefer isolated areas for nesting (Mehta 2020). Previous studies indicated that disturbance is one of the major factors for avoiding nesting habitat by Storks (Bouton et al., 2005). We also observed the permanent roosting sites of the Indian eagle-owl (Bubo bengalensis) nearer to this bridge (25° 8'16.12"N, 75°47'27.02"E). Likewise, we observed number of direct sighting of otters and crocodiles near as well as downstream regions of bridge when compared to other segments of the rivers. Moreover, the water quality parameters examined were within the normal range of river water quality. Thus, the present study revealed that the presence of cable-stayed bridge does not have any negative impact on the aquatic wildlife and quality of habitats in the Chambal River.