Water sustainability inside your home
- 1. Water and you What you do makes up the bigger picture
- 2. How much water do I use ? Real Consumption range : from 50 to 300 liters per person per day National Town planning Norms : Urban : 135 Lpcd Rural (Karnataka) : 55 Lpcd Use Litres/person Drinking 3 Cooking 4 How much Bathing 20 Water do Flushing 40 YOU Washing-clothes 25 Washing Utensils 20 Gardening 23 Total 135 Use ?
- 5. What about the rain ? : Local hydrologic cycle Site : 30 * 40 (Area 110 sqm) Annual rainfall on it in B’lore : 106700 Litres Before construction After construction Runoff : 10% 10670 Litres / annum Runoff: 80% 85360 Litres / annum Difference :74690 Litres / annum Who should manage this excess ?
- 6. Let’s look at the numbers more closely….. Rainfall Water falling on the roof (30 * 40 site) 10 mm (small shower) 1000 litres 30 mm (Average shower) 3000 litres 60mm (heavy shower) 6000 litres Annually in Bangalore – 970mm 87300 litres 4 member household, @ 135 lpcd needs 540 litres / day i.e. in Bangalore there is enough rain falling for 161 days of a family Or For nearly 5.5 months of the year that is Almost 50% of a household’s needs !!! Can we capture this store it or recharge it into our borewells (or can we do rainwater harvesting) ?
- 8. Most important principles of RWH – 2: Rainfall pattern & Geology Bangalore: MONTH DAYS QUANTITY (mm) JAN 0.2 2.70 FEB 0.5 7.20 MAR 0.4 4.40 APR 3.0 46.30 MAY 7.0 119.60 JUN 6.4 80.80 JUL 8.3 110.20 AUG 10.0 137.00 SEP 9.3 194.80 OCT 9.0 180.40 NOV 4.0 64.50 DEC 1.7 22.10 TOTAL 59.8 970.00 Rainfall more evenly spread better for Direct storage and Use. Geology and aquifer regime to be suitable for recharge. Recharge to be designed for local conditions. Thumb rule : Open wells good in deccan plateau. Depth of well necessary different in different place. 20ft minimum thumb rule.
- 9. RAIN WATER HARVESTING FOR HOUSEHOLDS : Quantity, Bangalore Tank Size Study 300 Days serviced 250 200 150 100 50 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 Tank sizes Household Rainwater Harvesting: Plot size Area Sft in Area SqM 30x40 1200 111.52 40x60 2400 223.04 In Runoff for a Runoff 30mm rain 60mm (Liters) (Liters) for a Annual rain (Liters) 3,011.15 6,022.30 97,360.59 6,022.30 12,044.61 194,721.19 Runoff
- 10. Most important principles of RWH – 1: Catchment and type of harvesting Direct Storage & Use CLEAN CATCHMENTS STORAGE : SUMPS, RAIN BARRELS (etc) Recharge NOT-SO CLEAN CATCHMENTS RECHARGE : OPEN WELL, DIRECT BOREWELL RECHARGE, (etc)
- 11. ….So how clean is Rainwater ?.... A Bucket of Rainwater in Kurubarakunte village, Bangalore Rainwater in a Glass Cauvery water in a Glass Guess Which is which ?
- 12. ….Really as clean as your roof (catchment) is… Clean Rainwater comes from Catchments that are clean – Roof tops are the cleanest Catchment. Keep your roof clean : No junking, no pets, no crackers, no holi, No chemical pesticides/fertilisers on the roof Managing Rainwater Quality : rainwater picks up contaminants from : 1. Urban pollution – First Rain separation 2. Contamination from the catchment – Catchment management, Pre-filtering 3. Rainwater has low TDS, low Hardness and low all other counts !!! Rainwater, for drinking will need Point of Use treatment for Bacterial contamination Eg: SODIS, Good rolling boil, Aquaguard etc.
- 13. Site Selection for Infiltration Many factors affect the suitability of a site as an infiltration facility for the disposal of stormwater. Among these, the following are most important: • Depth to groundwater • Surface soil type • Underlying soil type • Vegetation cover of the infiltrating surface • The uses of the infiltrating surfaces • The ratio of tributary impervious surface to the infiltrating surface
- 15. Recharge pit around bore wells
- 16. The making of a recharge well Pit and concrete rings The pit has reach the silt layer Placing of the rings
- 17. Recharge wells details Covers : grilled or perforated RCC Silt and leaves trap in a stormwater drain
- 18. Recharging a bore well Outlet pipe in recharge well Rainwater sent for recharge
- 19. Don’t forget the maintenance
- 20. Building bye-laws in Bangalore • ALL buildings with roof area more than 100 square metres • 20 litres for every sq. mt. (storage or recharge) • 60 litres for every square metre for more than 5000 square metre plot size
- 21. Demand – the heart of the scarcity problem What else can you do? Reuse Waste Water (eg: Grey for flushing, Treated black/grey for irrigation) And use the treated waste water to irrigate Your roof farm that produces food
- 22. Water harvesting and grey water reuse in a house
- 25. Turn sewage to a nutrient through Eco-san