Pollutants and Water Management. Группа авторов

2.6 Monthly temperature variations.

      2.3.2 Hydrological Variation

The hydrological regime of the wetland is highly variable throughout the year. Therefore, a contour line map of water availability in different months, i.e. October, December, March, and June during the study period was prepared and depicted in Figure 2.7. The average water spread was recorded to the maximum extent in October. Later, it started decreasing in December, followed by June, and the minimum water spread was in March. This is an indication of un‐uniform water availability and a pattern of siltation across the wetland. It also clarifies that in the lower stretch of this wetland, the pattern of siltation is more frequent, followed by the upper and middle stretches. The most frequent pattern of silt deposition in the lower stretch could be due to its existence toward the outlet channel of the wetland, which is not appropriately managed, and the runoffs from the whole catchment are drained to this part.

Figure 2.7 Contours lines based on water availability in different months in the Kanwar wetland by using Landsat 8 data from 2014 to 2017 for October, December, March, and June.

      2.3.3 Land Use Land Cover Change

The natural land cover in the wetland area was identified into four classes, i.e. waterlogged, open/scrub, agriculture, and settlements. In this study, the change in the LULC pattern under the classes was analyzed for the years 1988 and 2016, which is depicted in Figure 2.8. In 1988, the maximum area (59.58%) of this wetland was covered with water, followed by scrub/open (39.79%), agriculture (0.39%), and settlement (0.25%), but in 2016, waterlogged and scrub/open area were reduced to 35.84 and 29%, respectively. The average rate of the LULC pattern is shown in Table 2.2.

Figure 2.8 Area under four land use land cover change class in 1988 and 2016.

Table 2.2 Land use land cover change analysis in the Kanwar wetland between 1988 and 2016.

LU/LC class	Feb. 1988	Feb. 2016	Change	% Change	Yearly change (ha/year)
Water (ha)	1399.95	842.29	−557.66	−39.83	−19.92
Scrub/Open (ha)	934.94	681.67	−253.27	−27.09	−9.05
Agriculture (ha)	9.14	653.02	643.88	7044.64	22.99
Settlement (ha)	5.81	172.89	167.08	2875.73	5.97
Total area (ha)	2349.84	2349.87	–	–	–

      2.3.4 Water Quality

The water samples were analyzed for 17 parameters and compared with standard permissible limits. Some of the parameters with the previously reported values for the same wetland in this study are shown in Table 2.3.

Further, an overall WQI was calculated by adopting standard procedures proposed in various studies (Tiwari and Mishra 1985; Dwivedi et al. 1997; Trivedi 2010; Shah and Joshi 2017) and is shown in Figure 2.9. The overall WQI was recorded in the medium range, which is not safe for direct consumption without disinfection as per the guidelines of the Water Environment Partnership in Asia (WEPA n.d.).

Table 2.3 Water quality parameters of the Kanwar wetland.

Parameters	Current study	Permissible limits	Year 2002 a
Year	2014	2015	2016	Average ± SD	IS:2296 b
pH	7.89	8.41	8.25	8.18 ± 0.26	6.5–8.5	7.83
EC (μS/cm)	126.32	290.93	323.93	247.06 ± 105.86	1000–2250	204.24
DO (mg/l)	7.24	7.24	3.92	6.13 ± 1.91	4–6	6.04
Alkalinity (mg/l)	298.28	244.39	218.89	253.85 ± 40.53	(200–600)c	122.9
Hardness (mg/l)	303.89	290.36	193.67	262.64 ± 60.11	300–600	130.28
Phosphate (mg/l)	0.07	0.01	0.10	0.06 ± 0.04	NA Скачать книгу В начало < 16 17 18 19 20 21 22 23 24 25 > В конец