4. Discussion and conclusion

highest and lowest values (71.6 and 2.0 mg/L) for alkalinity were measured in November and September, respectively (Tables 8, 11). The highest and lowest values (3418 and 22 mg/L) for Cl were measured in March and May, respectively (Tables 7, 13). The highest and lowest values (1231 and 21 mg/L) for Na were measured in November and May, respectively (Tables 10, 13).

Table 12. Physicochemical analysis of water sample of station 9. Saedo Pattan Lake.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temp: Air 21 23 26 34 38 41 42 37 32 28 23 20 Tem: Water 19 20 23 30 35 38 39 34 29 25 20 17 pH 7.9 7.7 7.8 7.6 7.3 7.5 7.1 7.4 7.0 7.3 6.9 7.2 EC 1263 1143 1172 1092 938 1286 1027 1167 1263 1342 1495 1275 TDS 729 720 628 612 510 664 543 675 692 754 808 785 Turb 31 32 28 29 25 26 27 28 30 27 33 30 Ca 58 55 50 52 40 48 46 50 53 57 64 60 Mg 49 47 46 43 36 44 42 45 47 53 56 51 Hard 328 345 275 263 204 289 232 254 245 316 390 327 Alkal 4.3 4.4 4.0 4.1 3.9 4.7 4.1 4.4 4.2 4.5 4.8 4.6 Cl 152 148 138 119 110 134 126 160 135 145 166 141 Na 141 128 136 130 106 128 124 133 130 140 150 137 K 17 14 16 15 12 13 4 11 5 9 18 17 SO4 239 215 143 178 137 198 153 232 172 214 260 243 HCO ———————————— HCO3 210 225 189 194 145 178 162 196 186 224 240 210 BOD 3.8 3.7 3.5 3.6 3.3 3.5 3.0 3.4 3.1 3.2 3.6 3.3 DO 5.0 4.8 4.9 4.9 4.8 4.7 4.8 4.8 4.9 4.8 5.0 4.8

K 67 70 53 56 47 58 52 60 62 57 72 55 SO4 386 357 274 290 218 287 274 370 326 365 403 378 HCO ———————————— HCO3 3428 3294 3028 3125 2793 2880 2983 3145 3218 3472 3580 3356 BOD 3.9 3.6 3.2 3.3 3.4 3.7 3.5 3.8 3.6 3.5 3.8 3.7 DO 5.6 5.5 4.8 5.3 5.0 5.1 5.2 5.0 5.4 5.7 5.8 5.2

Table 11. Physicochemical analysis of water sample of station 8. Old Nara Lake.

Parameters Months

74 Community and Global Ecology of Deserts

Parameters Months

The Nara Desert Wetland Complex (NDWC) encompasses sandy dunes, steep hills and includes low lying flat zones associated with different natural wetlands formed from the seepage of Nara Canal. These different wetlands are the major perennial source of water for the agricultural lands, local communities, wildlife and grazing livestock. NDWC comprises more than 225 seasonal and permanent, small, medium and large-sized lakes/wetlands. The total area of Nara Canal is distributed from Sorah (Sukkur) to Head Jamrao about 108,960 hectares and Nara Canal was declared in 1972 as a Game Reserve area for the protection of wild animals. The NDWC is also recognized as an essential potential Ramsar Site [1–5]. The different floral habitation distributed in the Nara Desert includes phytoplankton, reed vegetation, herbs, shrubs and trees. The area is ecologically-rich with the faunal biodiversity which includes zooplankton, invertebrates, fishes, amphibians, reptiles, birds, small and large mammals. The NDWC has received high economic, social, floral and faunal habitats, and aquatic biodiversity values because the local communities are directly or indirectly dependent on these natural sustainable resources [1–4, 7, 29, 35] (Figure 7).

the EC, TDS concentrations were found to be higher than the WHO standard. The Na is the major solute that can also affect aquatic biodiversity [37]; Na concentrations during the study period were higher than WHO accepted standard in most of the wetlands in the NDWC. The WHO recommended that the tolerable level of Cl is 250 mg/L [34]. In this study, the various wetlands had higher Cl concentration than the acceptable WHO standard. However, the concentrations of Ca, K, SO4, HCO3, BOD and DO were higher than the acceptable WHO standard in

Ecological and Environmental Assessment of Nara Desert Wetland Complex (NDWC), Khairpur, Sindh-Pakistan

http://dx.doi.org/10.5772/intechopen.78623

77

In the study area, quality of water is mainly sweet and acceptable for drinking purposes. The range of Total Dissolved Solids (TDS) reported between 500 and 800 ppm. In the area, there are also few brackish wetlands reported and TDS varies between 10,000 and 28,000 due to recharge of insufficient amount of water. The quality of ground water is mainly dominated by sulfate, chloride, calcium and magnesium ions [16, 38, 39]. The conductivity (or TDS) is major parameter along with pH in recognizing the water quality. The values of both parameters is considered acceptable in freshwater lakes while it is otherwise considered the saline lakes. If the value of turbidity is higher than considering alkaline water while above the WHO standard level of 5 NTU. The value of higher turbidity may be due to discharge of waste materials and agriculture run off. The Nara Canal is originates from the Indus River. The water in the Indus River is generally contaminated carrying organic and inorganic polluted particles load from the upstream due to anthropogenic activities. The Sindh Environmental Protection Agency (SEPA 2002) recorded that the value of BOD in Indus River is exceeds more than 6.5 mg/L, which is also recognized by Global Environmental Monitoring System (GEMS) the water of Indus River is highly polluted. According to microbiological analysis of water by WWF-Pakistan (2007) confirmed that in the two sites the presence of fecal coliform. The availability of Fecal coliform in the water system is considering harmful for the human population consumption which may cause water borne disease. In freshwater bodies the availability of Fecal coliform is an indicator of

The parameters of water were only collected to examine the quality of water for the purpose of drinking. Although, it has also been reported that the more than 100,000 fisherman population who were directly associated with the fishery occupation have suffered a lot in the recent decades. In the wetland complexes the higher amount of inflow of saline effluent has causing

Hunting: In the study area, the hunting for recreation is observed common and uncontrolled. However, the region is protected but there is no effective implementation of the wildlife laws for the wild animals. Due to hunting pressure, this is also leading to imbalance between the

Foraging of Livestock: The large amount of grazing livestock in the area together with the

Cutting trees: In the study area, the cutting of trees in the adjoining desert region for continuous practice of conversion of lands into agricultural fields which is affecting the wild population.

recent climatic changes is degrading the food chain in the ecosystem dynamics.

the most of selected wetlands during the study period.

contamination with the human and animal excreta [5, 7, 36, 38, 40, 41].

in the devastation of the lake [7, 40].

predator and prey species.

5. Threats

In the area the water quality and recharged by the Nara Canal is mainly sweet and acceptable ranges of TDS between 500 and 800 ppm except hypersaline lakes. The hypersaline water of desert area is mainly observed brackish which have TDS between 10,000 and 28,000 pp. [5, 36].

The climate of the area is mainly arid having high temperatures and late summer rains observed. The seasonal rainfall is varied and is less than 250–300 mm and rainy season usually starts from June to September. Before the monsoon season, the average temperature is exceeding 45C in the desert region and in the plains of NDWS the average temperature between 30 and 40C. The wetland complex is recognized of great hydrological values as 98% Nara Canal water is used for agriculture and only 2% water is used for domestic and drinking purposes. The wetland complex of Nara Canal is 361.6 km long and 90–135 m wide. The maximum water depth of wetland complex is 7.5 m. The highest water discharges of Nara Canal are reported in the months of May–July and the minimum water flow in the August [1–4, 7].

The assessment of physicochemical parameters such as pH and alkalinity revealed that the lake water has mostly remained alkaline during the whole study period except the Nara Canal station due to its input of rain water. The range of hardness was higher in most of the selected lakes of NDWC. The acceptable level of hardness in lake waters is recognized as 200 mg/L by the World Health Organization [34]. The physicochemical parameters of Na and Mg, as well as

Figure 7. A view of Nara Canal Khairpur.

the EC, TDS concentrations were found to be higher than the WHO standard. The Na is the major solute that can also affect aquatic biodiversity [37]; Na concentrations during the study period were higher than WHO accepted standard in most of the wetlands in the NDWC. The WHO recommended that the tolerable level of Cl is 250 mg/L [34]. In this study, the various wetlands had higher Cl concentration than the acceptable WHO standard. However, the concentrations of Ca, K, SO4, HCO3, BOD and DO were higher than the acceptable WHO standard in the most of selected wetlands during the study period.

In the study area, quality of water is mainly sweet and acceptable for drinking purposes. The range of Total Dissolved Solids (TDS) reported between 500 and 800 ppm. In the area, there are also few brackish wetlands reported and TDS varies between 10,000 and 28,000 due to recharge of insufficient amount of water. The quality of ground water is mainly dominated by sulfate, chloride, calcium and magnesium ions [16, 38, 39]. The conductivity (or TDS) is major parameter along with pH in recognizing the water quality. The values of both parameters is considered acceptable in freshwater lakes while it is otherwise considered the saline lakes. If the value of turbidity is higher than considering alkaline water while above the WHO standard level of 5 NTU. The value of higher turbidity may be due to discharge of waste materials and agriculture run off. The Nara Canal is originates from the Indus River. The water in the Indus River is generally contaminated carrying organic and inorganic polluted particles load from the upstream due to anthropogenic activities. The Sindh Environmental Protection Agency (SEPA 2002) recorded that the value of BOD in Indus River is exceeds more than 6.5 mg/L, which is also recognized by Global Environmental Monitoring System (GEMS) the water of Indus River is highly polluted. According to microbiological analysis of water by WWF-Pakistan (2007) confirmed that in the two sites the presence of fecal coliform. The availability of Fecal coliform in the water system is considering harmful for the human population consumption which may cause water borne disease. In freshwater bodies the availability of Fecal coliform is an indicator of contamination with the human and animal excreta [5, 7, 36, 38, 40, 41].

The parameters of water were only collected to examine the quality of water for the purpose of drinking. Although, it has also been reported that the more than 100,000 fisherman population who were directly associated with the fishery occupation have suffered a lot in the recent decades. In the wetland complexes the higher amount of inflow of saline effluent has causing in the devastation of the lake [7, 40].
