Drainage network and Land cover of the wetland region were mapped using temporal Google earth  (http://www.googleearth.com) for the period 2007 to 2012, and the changes in landuse and drainages (network as well as width of the channel/drain). Figure 7depicts drastic land use changes evident from the conversion of wetland to open land (at the proposed SEZ site) during 2000 to 2012. Temporal change analysis done for the region is given in Table 1. Figure 8 illustrates land use changes between 2007 and 2012.Wetlands have decreased from 32.8 Ha to 5.95 Ha whereas the Open land (Conversion of Wetlands to SEZ Construction site) has increased from 0.6 Ha to 27.46 Ha.

Table1: Change in Land use

Figure 7: landuse in the  SEZ region during 2000  and 2012

Figure 8: Change in wetland between 2007 to 2012

Figure 9: Change in drain network

The change in drainage pattern between 2007 and 2012 is shown in figure 9 and table 2 gives the extent of encroachment of drainage and wetland.

Table2: Encroachment of drainage and wetland

Effect on vehicle traffic in the region: Figure 10 gives the existing road network (Main Roads) in the region; the length between 2 signals on either side of the SEZ is approximately 1.88 km (Google Earth) the width of road is 15.5 m, 4 lanes and two ways. The capacity of urban roads is listed in table 3.

Table 3: Capacity of urban Roads as per IRC

Road maximum capacity: As per IRC (http://www.irc.org.in- Indian Road Congress) for a 4 lane road with traffic flow on both sides, for roads with no frontage access, no standing vehicles, very little cross traffic (intersection) capacity is 4000 PCU/hour (PCU- Passenger Car Unit).  The capacity for Sarjapur road was estimated to be 3500 PCU/hour, on either side of the road, with average length of a PCU as 4m at an average speed of 45kmph and driver reaction time of 0.7 seconds.Along sarjapur road, during the highest peak hour traffic, the number of vehicles is approximately 2000 PCU’s/hour. With this the level of service (LOS) based on the ratio of observed to maximum capacity is

V/C = 2000/3500 = 0.571

For the ratio of 0.57, the current Level of service in under category “C” as per Table 4.

Figure 10: Bellandur Catchement Road Network

Table4:  Category of Roads based on traffic and service

The SEZ has a capacity of over 14000 Car units, in addition to this because of the Floating population that travel in their own mode of transit yields an additional vehicular population.

With added 14000 cars, assuming 8 hour of traffic in a day, the density of car units would increase by 1750 units per hour increasing the traffic to 3750PUC’s/hour. Then the V/C ratio is 

V/C = (2000 + 1750) / 3500 = 1.07

The ratio of 1.07 is equivalent to an LOS category of “F” indicating very very poor traffic conditions indicating higher chances of traffic congestion. The current bottle necks along the Sarjapur Road is as depicted in figure 10(a) and likely bottleneck due to the addition of 14000+ vehicles, is depicted in figure 10(b). Traffic bottlenecks also have higher levels of pollutants such as particulate matter, CO₂, NO_X, SO₂.

Figure 11:  Traffic bottlenecks