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Understanding HalanayakanaHalli lake
- 1. Halanayakanahalli Kere Halanayakanahalli kere lies in the Sowl kere watershed and is part of the cascading tank system that is upstream of Sowl kere. The lake is surrounded by busy public roads on all sides and hence open to public at all times. It lies to the north of Rainbow Drive and is one of the sources of the flooding that the gated community experiences during heavy rains. On 14th December 2022, Biome along with members of the RBD went around Halanayakanahalli kere to survey the area to see what can be done to improve the flooding issue. This document outlines the findings from that undertaking.
- 2. ● Overview of Halanayakanahalli Kere ● Halanayakanahalli Kere ● Temporal changes of Halanayakanahalli Kere ● Topography/Elevation map of Halanayakanahalli Kere ● Natural Drainage map of Halanayakanahalli Kere ● Watershed of Halanayakanahalli Kere W.R.T Rainbow Drive ● Observations after survey for Halanayakanahalli Kere ● Natural drainage and watershed of Junnasandra kere ● Observations after survey for Junnasandra kere Content
- 3. Overview of Halanayakanahalli Kere Saul Kere Bellandur Kere Varthur Kere Halanayakanahalli Kere ● The Halanayakanahalli Kere is part of the Saul Kere’s Watershed. It is one of the Upstream lakes of Saul Kere. ● The drainage flow is from South to North. ● The Kere covers an area of approx 64.7Ac at an elevation of 890 mts above sea level. ● It has two upstream lakes Choodasandra Kere, Hadosiddapura Kere. Natural Drainage network and watershed is created using SRTM DEM data dated Feb 2000. Lakes, watershed outlines are mapped manually using LANDSAT satellite data. Drainage Flow Direction
- 4. Observations based on Satellite Data ● In 2002 - Command Area was approx 8.39 Ac. ● Since 2002 it is observed that the Kere had small command area ● Most of the downstream area near the kere has always had more trees than crop/irrigation. The inlets, Outlets, Command area are all mapped manually using satellite data based on LANDSAT DATA Dated January 2002 Halanayakanahalli Kere in 2002 Command Area Halanayakanahalli Kere Choodasandra Kere Hadosiddapura Kere Inlet Inlet Inlet Sluice gate Kaluves Inlet Drainage Flow Direction Sluice gate
- 5. Temporal changes in Halanayakanahalli Kere Timeline 2002 > 2014 > 2022
- 6. Halanayakahalli Kere part of Saul Kere watershed in 2002 2002 Halanayakanahalli Kere Choodasandra Kere Hadosiddapura Kere Quarry Lakes Inlets Sluice Gate Outlet Command area Sarjapura Road Junnasandra Kere
- 7. 2014 Halanayakahalli Kere part of Saul Kere watershed in 2014 Halanayakanahalli Kere Choodasandra Kere Hadosiddapura Kere Old Quarry Lakes Inlets Command area Sarjapura Road Junnasandra Kere
- 8. Halanayakahalli Kere part of Saul Kere watershed in 2022 2022 Halanayakanahalli Kere Choodasandra Kere Hadosiddapura Kere Old Quarries Lakes Inlets Command area Sarjapura Road Junnasandra Kere
- 9. Topographic and Elevation map of Halanayakanahalli Kere Ridges of the watershed Halanayakanahalli Kere Choodasandra Kere Hadosiddapura Kere Saul Kere ● The highest points (Ridges) of the watershed are at 920 masl and the kere is at 890 masl. ● While the downstream area of the kere is at elevation of 885 masl. ● The region from the HalanayakanaHalli kere downstream to Saul kere across the Sarjapura road (indicated in Red arrow) ● The slope gradient (change in slope) is only 5 meters over a distance of approx 1.8km making it a area with very gentle slope. Drainage Flow Direction The elevation, contours and natural drainage maps are created using SRTM DEM data dated February 2000. The lakes are mapped manually using LANDSAT Data. Junnasandra Kere
- 10. Halanayakahalli Kere Halanayakanahalli Kere Choodasandra Kere Hadosiddapura Kere Ridges of the watershed ● It is observed that in the events of rainfall for long hours or heavy rainfall in very short period of time (called as cloud bursts) causes: 1. The water overflows over the bund which is a road now. Reasoning: Can be due to elevation of waste weir higher than required/thin outlet? choked outlet? 1. The runoff happens in sheet form. Reasoning: Can be due to absence of any natural/artificial channels/ drainage and gentle sloping of the downstream area causes the sheet flow? Drainage Flow Direction Junnasandra Kere Saul Kere Wastewater Sluice gate
- 11. Major and Detailed Natural Drainage map of Halanayakanahalli Kere The natural drainage lines are created using SRTM DEM satellite data. The detailed and Major drainage show the natural drainage pattern with respect to the topography and elevation Major drainage Detailed drainage Halanayakanahalli Kere Choodasandra Kere Hadosiddapura Kere Saul Kere Bellandur Kere Halanayakanahalli Kere Choodasandra Kere Hadosiddapura Kere Saul Kere Bellandur Kere Junnasandra Kere Junnasandra Kere
- 12. Halanayakanahalli Kere Watershed Halanayakanahalli Kere Choodasandra Kere Hadosiddapura Kere Inlet Inlet Junnasandra Kere Drainage Flow Direction
- 13. Junasandra Kere and HNhalli Kere Watershed Watershed Halanayakanahalli Kere Choodasandra Kere Hadosiddapura Kere Junnasandra Kere
- 14. Drains passing through Rainbow Drive Rainbow Drive Halanayakanahalli Kere Choosandra Kere Hadosiddapura Kere Junnasandra Kere Drainage Flow Direction
- 15. Flow from Junasandra lake and neighbourhood houses Sluice Gate Solid Waste Dumping Inlet-1 Inlet-2 Inlet-3 RBD Junasandra Lake Merge of Junasandra and HKhalli Lake O v e r f l o w
- 16. 1. Solid waste was dumped in and around the Lake and at the inlet of the drains (refer previous slide for dumping points). 2. Cleaning of the Lake can be taken as an immediate action to improve the health of the lake 3. No direct sewage water entries into the lake was found but an eye needs to be kept on this in future visits as this these channels are not controlled/protected in any way. 4. Neighborhood houses and apartments are letting their sewage water into the stormwater drains. 5. The stormwater drain connecting Junnasandra lake and Halanayakanahalli lake flows into the Rainbow drive layout; this Nala needs to be extended to direct this water to drains that connect to the Sarjapur road stormwater drains. 6. The sluice gate is dysfunctional though, water might still be moving to the command area through this. 7. Outlet channel is blocked by a road (as seen in the previous slide). Hence, overflow from the lake floods this and other connected roads in area. Pointers after Halanayakanahalli Kere Survey
- 17. Thank you