Virtual tour of Rainwater harvesting theme park!

 What does a Non-resident think about her Rain-water harvesting theme park visit and what learning does she take from here? 

As our guide opens one of the sump tanks to show what’s inside it, all of us present moved towards it slowly in curiosity with 8th standard students giggling, whispering and struggling to find their way to come forward. To maintain the decorum and bring student’s attention back our guide asks them to remain 1 feet away otherwise somebody might fall into it. He asks what do you think what’s inside?  There is nothing ‘it’s water only’ and that caused us to burst into laughter.  

As I enter the Rainwater Harvesting Theme Park I see a small standing statue of M.Visvesvaraya under the wide punched sky telling the story of the legacy he left behind. This park innovatively amalgamates technology to exhibit live rain-water harvesting models, structure and their functioning. These simulation models allowed all of us to understand the nitty-gritty that goes into the installation, costing and functioning of the system.  It allowed us to engage with real things in an experiential way. There were two sections to the park, one is  an open space where RWH systems, recharge wells, sump tanks and traditional method of RWH (Which looked to me as some magical pond reflecting the sky and a small tree that reminded me of Fairy Tales) and water wise gardening is exhibited, the other section enclosed by a roof has three galleries namely Water Gallery, Sewerage Gallery and the Centralized Gallery. The entire Gallery is a knowledge hub and the simulation model installed there adds fun to the learning process as we ourselves engage and interact to ponder over some of the critical questions.

  Magical Pond?

 We started our tour at 11:30 along with 8th standard students who also accompanied us to make sense of the bookish knowledge disseminated inside their 4-walled classrooms. Our Guide, Mr. Nikhilesh patiently makes us familiar with all the installations, types and structures exhibited there. As all the students take out their diaries to jot down all the key points we also start making notes but in our virtual diaries i.e our phones. A small tangent here experts say that writing down with your own hands increases your memory and retention power. As we continue with our tour, to bring back the attention of the 8th standard batch our guide addressing the students says, I will ask questions to check whether you are able to follow. This hit me with a thought that we are at a position where we are on our own, accountable to our own selves and nobody else

Banglore, silicon valley of India is  also known for its gardens, man-made tanks and people who take pride in the city’s heritage and what it serves. In the midst of the busy city, crowded metros, places like rain water harvesting theme parks and other parks bring in the calmness even if it's sporadic. The rapid urbanization and increased population is adding pressure on all the limited sources that we have. Post 1980’s the trend of digging borewells started which eventually resulted in water deficit i.e the extraction of groundwater was in excess than the recharge of the aquifers. Not only was the quantity affected but the quality also deteriorated in some pockets where industries were popping up. Rainwater Harvesting is a simple and traditional practice of harvesting the rainwater that assists in recharging the groundwater and acts as a derisking mechanism. It can build resilient communities as the competition for the resources with increased population becomes more fierce. When we say innovative ways we don’t have to invariably think about technological changes as Mr. Avinash Krishnamurthy aptly puts it: “Technology is taking science out of our lives, and we must understand that Sustainability is Science”. This highlights the significance of Nature based solutions and simple techniques like RWH that can be implemented easily. 

Virtual Tour of RWH Theme Park

Every house will have a roof having a small gradient from where all the water will go to the downward pipe i.e catchment area. The three basic components of RWH are catchment, conveyance and storage. Conveyance is the pipe which conveys the water to the filtration unit. There are two types of filter: one is a wall mounted filter and another another one is a centralized filter. You can either utilize this water or let it  recharge the groundwater. Wall mounted filter is better for small houses. While collecting water in the wall mounted filter the principle of first flush should be taken care of which means the first 5-10 mins of rainfall should not be collected as it contains more impurities and contaminants. The water in the wall mounted filter will filter the rainwater from physical impurities and not from chemical impurities. After the water is filtered it can be stored in a tank called a sump tank. The stored water can be used for secondary purposes other than drinking and cooking. 

In big buildings like vidhana soudha, HC wall mounted filters are not feasible. For large buildings the alternative is a centralized filter.  In any filter there are two chambers. First one is the first flush chamber which is designed according to the volume. Second chamber has the sand bed filter; it will filter both chemical and physical impurities. Once the sump fills up to its brim, water  will overflow and will recharge the wells and percolate down into the groundwater.

These recharge wells are 25 feet deep. In residential buildings minimum depth should be 10 feet because we will have a foundation that go upto 6 to 7 feet deep. In order to bypass that foundation it’s better that we go 10 to 15 feet deep. Covering  it with 40 mm aggregate will prevent the silting because if silting happens it will lose its previousness.

V wire  technology is not advisable. In a Strata there is a rock which you can’t recharge, a borewell is drilled to bypass the rock strata and on top of it you will have filter media and a feeding channel, overflow water will come here and the water will be directly injected into your aquifers. It is  not advisable because of easy contamination of the groundwater and considered as the unscientific way of Groundwater recharge.

Stormwater Drain

Water Wise Gardening

It was indeed a meaningful and a valuable experience. Theme parks like these are an innovative way that assist in wide outreach to the citizens. Combining it with the mandatory legislation allows citizens to understand the need and potential of RWH in sustainable management of the Groundwater. Though in physical terms we are talking about something that is beneath the ground, its sustainable management and care would result not only in the availability of enough water but it will also provide avenues to stride up the ladder to make Bangalore a more progressive city.  

Gallery

Trees planted according to Zodiac Signs

 Pervious Pavers: These pavers will allow 5-10% of rainfall to percolate down into the earth. 

"Every drop of water counts"

O Mittur Lakes Monitoring

On June 30 and July 1, 2022, a visit to O Mittur Panchayat in the Kolar district was made. The four lakes we visited as group four were Chikkakere, Hosakere, Shakti Kunte, and Doddakere. The goal of this project was to monitor lakes using standardized protocols. These protocols included requirements for measuring the size of lakes, their elevations, the crops that were cultivated in the command area, the quality of the water, and the socioeconomic state of the community. Shubha Ma'am, Suma Ma'am, and Asha, the founder of the non-profit organization Grameena Abhivrudhi Sangha, who served as our translator, guide, and mentor, were present during the survey, along with the locals who live close to the lakes.

Chikkakere Lake:The 25-acre Chikkakere Lake (Tank No.365) is situated in the Kolar district's O Mittur (Urukunte Mittur) settlement. 

Hosakere Lake:Hosakere lake (Tank No.124) , spread across 30 acres is located in Kottur village.

Shakti Kunte Lake : Shakti Kunte lake (Tank No. 46) which is 300 years old  is located in the Bandahalli village of Kolar district. 

Doddakere Lake : Doddakere lake ( Tank No.62)  in the Avala Marakalagatta village is approximately 10-12 feet deep.

 

Observations made about the lake's characteristics included:

The common theme that was seen while keeping an eye on the four lakes is that the water inside the lake is used for livestock management and irrigation rather than for drinking. The majority of farmers in all the communities depend on agriculture for their primary source of income, but they also engage in allied agricultural activities, particularly in the summer when water stress is most noticeable.Currently most of the villages have borewells for drinking water purposes.Two significant issues that continue to plague Hosakere and Doddakere Lake are desilting and bund leaking.In Chikkakere Lake, the Kaluves (feeding channel) is inoperative. Since the Raja Kaluve (feeder canal) is clogged with silt, a suction pump is used to push water straight from the lake.Kalyani or stepped temple tanks are present adjacent to Chikkakere Lake.A sacred idol that can be seen nearby under a peepal tree close to the Chikkakere lake serves to further underscore the location's religious significance.The cost of the Hosakere Lake bund leak is estimated to be between 10 and 12 lakhs. Desilting should be carried out under the panchayat's supervision, but this has never happened.

Societal issues

Regarding pay inequalities, certain societal problems were also noted. Many of the people we spoke to held the view that men get more money because they put in more work than women do, including Shivananda, a farmer in Kottur. Concern should be expressed about the speed of immigration, which makes it impossible for immigrants to live comfortably in cities and forces them to live in subpar housing.

As it is uncommon for women in the village to own cars and drive, there are mobility issues for women as well. Asha from Arohana expresses her enthusiasm to learn to ride a scooter. Women's empowerment is hampered by this restriction on their freedom of movement.

Biodiversity significance:

Numerous biodiversity species have been found over the entire region. Lantana Camara, Pongamia Pinnata, Eucalyptus, Morning Glory, Peepal, Tamarind, Neem, and water lettuce are a few of the plant species that have been spotted in and around the Chikakere lake. While certain types of plants are good for the environment, others are not. As an illustration, Eucalyptus trees are charged with a number of offenses, such as ruining watersheds, causing erosion, igniting fires, and blocking indigenous vegetation

     

                                    Morning Glory                                     Pongamia Pinnata 

The lantana plant is a species of High Concern for India and one of the top ten most destructive invasive plants in the world. It interferes with the nitrogen cycle in the soil and challenges native plants for space and resources. Pongamia has several benefits to both people and animals. The production of this honey may be used by rural communities to boost their incomes and carry out apiculture. The leaves have a number of medicinal applications as well. The oil from the seeds can be used as a natural treatment for skin and rheumatic ailments. 

     

                                              Eucalyptus                                  Lanta Camara 

Detailed Report Link:

O Mittur Lake Monitoring Report

Sonnappanahalli: ‘A village of wells’

With the pet Dog hovering around Pommani, a resident of Sonnappanahalli Janta Quarters,  we listen to her keenly as she responds to our questions and describes her neutral water narratives. Sharing her water tales she mentions how the water from the nearby well is utilized for different purposes that fulfill the needs of the villagers. As she completes her response we immediately put up more questions to not miss out anything since these intimate interactions give insights about the situation at the ground level. While surveying the well and listening to Pommani some of the interns patted the dog affectionately as cool breeze wafts over the place that caresses us. Observing her closely while she was answering our interrogative questions, when asked whether they are satisfied with the water supply facilities she responds without any woes that we are satisfied and have no complaints. But unfortunately not all stories have a happy ending as we saw how the water stress in some of the pockets of the village had forced people some 25 years back to dig deeper to pump out more water from the water supply tanker well due to increased demand  and slow recharge rate of the groundwater. 

Sonnappanahalli, a village of wells located in Doddaballapur block of North Bangalore, spread across 128.04 hectares is governed by the panchayat. We started our visit at 9:30 and reached by 10:00 at Sonnappanahalli lower Primary school. This school is a good example of integrating sustainable models of wells and rainwater harvesting systems. As we roam around and observe, small kids giggle and greet us with ‘Hello Ma’am’. The school has a huge well in the backyard along with a sump tank and rainwater harvesting system inside the school. When we think of government schools we have a preconceived notion of poor facilities and education but here at our first impression we observed classrooms donned with wooden desks and decorated with all visuals to make children learn through observation. Sonnappanahalli has a number of wells located at around  every 80m, 150 m and some are located at a distance of 1km. While walking through the lanes we come across different wells and every well has its own story with unique design and periphery that defines Sonnappanahalli’s distinctive identity. These old wells dug some 50 or 60 years back are a cultural heritage that must be maintained not only to reduce the dependency on borewells but to revive the traditional practice of well digging and empower well digger communities that have been engaged in this profession for years. A walk through the village reveals a picturesque view with the sky punched with clouds, tracts of agricultural lands donned with banana plantations and other crops.

A common motif that was observed across all the locations where the wells are dug is that the water is not utilized for drinking purposes as the TDS (other factors were not taken i​nto consideration) is very high (>500) and the water is not suitable for drinking purposes. Some wells are abandoned and the water inside the wells is not utilized at all. Apart from improving the water quality of wells there is a great potential in channeling the water in Bettahalasur quarry for human consumption. Sonnappanahalli school is a good example of integrating sustainable models. Schools can be utilized for pilot study in order to ascertain the feasibility of water conservation and groundwater recharging systems. The wells that are abandoned can be revived and maintained so that water can be utilized by the people. We must collectively revive the legacy of Sonnappanahalli Village for which we have to ensure Community participation and democratization of the decision making process so that people are conscious of the significance of these wells. 

For the detailed description of the project the link to the report and the PPT is attached below:

Report: Sonnappanhalli's Larger Story Report

PPT:  sonnappanhalli Larger story

Hosakere lake

 Hosakere lake

Hosakere lake is situated in the Pichaguntahalli village of Kolar district in Karnataka. The total area of the lake is 19.18 acres.from last 2 year lake is maximum full to its capacity in august and september. The lake was desilted in 2003( JSYS+ world bank) and in 2021 slit is added back to the fields . as they are rich in nutrients. There is always a requirement of desiltation in the 8 to 9 year in a lake but it happens here after almost 18 year.for the desiltation process the local villager came forward to help in the process. The lady with whom we had interacted had more than 20 years of knowledge in the field of lakes. The demand can be made to the gram panchayat by the people for the betterment of the village. The daily Wages in the village is 297 to both men and women in the village by Nrega scheme.

Hose kere, Pichaguntahalli - Google Maps 

Downstream of the lake is Doddakere, Yalagondahalli and upstream is Talakunte. Water came from the Talakunte to the lake. 

Kolar is one among six permanently drought-prone districts in Karnataka. In 15 years to 2015, only three years in Karnataka–2005, 2007 and 2010–witnessed no drought, as per a 2017 Karnataka State Disaster Management Monitoring Centre’s drought vulnerability assessment report. The district has zero net groundwater for future use, and has the highest groundwater extraction – 211% – in the state, noted the 2017 Dynamic Groundwater Resources Assessment of India. The month with the most rainfall is September.

3 feeder channels coming from the catchment area are in use while one feeder channel is not in use anymore.

Feeder channel not in catchment area           

                       Feeder channel in catchment area

Feeder channel in catchment area 

Around 48 families live around the lake. Everyone around the lake and in the village uses the lake: farmers for irrigation, herders for cattle grazing, children for swimming and women for washing clothes and No, sewage does not enter directly into the Lake. The drip pipe has been provided to the small and marginal farmers by the government and everyone has adopted the drip irrigation system. Paddy and ragi are the crop cultivated in command area, There is a shift from manual cutting of paddy to machines. 50 people were required to cut paddy. The daily charges were Rs 400 per day for 4 to 5 hours. The machine achieves to cut paddy for over 1 acre in Rs. 4000. The machines have reduced the extra financial burden of the farmers. Crop grown in catchment areas is Beans,Tomato,Green chili. Sand mining was observed. Villagers extract mud to use in house foundations as well. This leaves depressions in the lake and affects the flow of water through the lake.

Waste weir of the lake

Wells

This farm has a private well 10 ft in diameter and 20 ft in depth. The well has 3 ft of parapet wall around it.

This farm well is 15 ft in diameter and 30 ft depth the well is completely filled with the water till the ground level and resembles

a pond.

Public farm well- 12 ft dia, 60 ft. This stone pitched well was built more than 50 years ago in two months with the help of 4 people.

The local language to measure the well is ‘murmuttu’ in the village. 1 murmuttu is equal to 20 feet.

Income resources of the villagers are agriculture, dairy and quarry. Quarry located on the east and south east side of the lake.

Quarry (east)

Quarry (South east)

Biodiversity Observations:

Trees: Peepal, Neem, Eucalyptus, Tamarind, Lantana Camara, Babool, Knotweed, Calotropis, Alchornea

Wetland plants: Typha, Alligator weed

Mammals: Mongoose, dog.

Birds: Pied wagtail, Spot-billed ducks, Jungle myna, Bee Eater, Silverbill, White-rumped swallow, Gray heron, Pond heron,  Purple herons, Pied kingfisher, Black drongo, Black-headed ibis, Red-wattled Lapwing, Paddyfield Pipit, Little cormorant, Shikra

Reptiles/ Amphibians: Rock Agama, toad, frogs

Insects: Butterfly, Damselflies, Dragonflies, spiders.

Bean

    

Lantana camara

                                             

                                                 

                                               Rock gam

                                               

                                               Typha

                                              

The correlation between the Tank system and Bengaluru's Topography

Bangalore District is located in the southeast of Karnataka State, in the centre of the South Deccan plateau, between the latitudes of 12° 39' North and 13° 18' North and the longitudinal meridian of 77° 22' East and 77°52' East. It has an area of about 2,191 square kilometres and an average elevation of about 910 metres (Bangalore rural and urban districts)

The Bangalore North taluk is more or less a level plateau and lies between 839 to 962 meters above mean sea level. In the middle of the taluk there is a prominent ridge running NNE-SSW. The highest point (Doddabettahalli 962m) is on this ridge. The gentle slopes and valleys on either side of this ridge hold better prospects of ground water utilization. The low-lying area is marked by a series of tanks varying in size from a small pond to those of considerable extent, but all very shallow.

Bangalore South Taluk represents an uneven landscape with intermingling of hills and valleys with bare rocky outcrops of granites & gneisses raising 30-70 meters above ground level are common in the southern portion. The highest point is 908m above mean sea level and the lowest at 720 meters above the mean sea level. Southern and Western portions present a rugged topography composed of Granitic and Gneissic masses. The eastern portions of the Taluk form an almost featureless plain with minor undulations.

Fig. 1: Bangalore's changing slope topography is depicted on a slope map as per percentage.

Contour lines are used to represent elevation. An elevation is represented by a contour line when it is drawn on a map. The elevation of each point on the map that touches the line should be the same. You can tell the height of a line on some maps by the numbers on the lines. Different altitudes will be represented by contour lines placed adjacent to one another. The slope of the terrain increases with the proximity of the contour lines to one another.

Fig. 2: Bengaluru's contours are shown on a map every 50 metres.

Interconnected tanks were made possible by the area's undulating geography, which ranged in altitude from roughly 600 m to about 962 m AMSL. Due to the abundance of tanks (approximately 285 tanks in a 161 sq km area, Bangalore's spatial extent , the city was once rightly referred to as the "city of tanks." To permit the transfer of excess water to the following lake, these tanks were all connected by canals and drains (kaluveys). These tanks served the region's fundamental requirements, including supporting food production (fish, etc.) and agricultural activity. They also provided drinking water for the community and habitat for fish and other aquatic ecosystems.
Bangalore City's naturally undulating landscape, which includes hills and valleys, is ideal for the creation of tanks that catch rainfall, store it for later use, and guarantee ground water replenishment. Thus, tanks are dynamic ecological systems that are essential for the survival of all species, including humans. When a lake in Bangalore overflowed, the extra water would flow into the next lake in the cascade because tanks in Bangalore were constructed in a cascade from higher to lower elevations. Along the land's natural gradient, water flows both north to south-east and north to south-west. There is a central ridge in the center of the region with maximum elevation 943, Minimum elevation 600 and average elevation in Bangalore city is 910 as per shown in Fig. 3. 

Fig. 3: Topographic variations in Bangalore city according to elevation

The elevation map depicts the land's varying elevations showing central ridge in the center of the region. Contour lines are used to represent elevation. An elevation is represented by a contour line when it is drawn on a map. The elevation of each point on the map that touches the line should be the same. You can tell the height of a line on some maps by the numbers on the lines. Different altitudes will be represented by contour lines placed adjacent to one another. The slope of the terrain increases with the proximity of the contour lines to one another
By holding vast volumes of water and releasing it when there is a shortage, a lake functioning properly can lessen the effects of floods and droughts. Additionally, tanks recharge groundwater and improve the water quality of downstream watercourses. Tanks often raise the lowest temperature year-round while lowering the maximum temperature. Bangalore has cooler climate because its elevation is more than 900 m above sea level. The more you go upward from earth’s surface, the average yearly temperature of a place decreases. That is the only reason. Any place of similar elevation (and located in a similar latitude) will be as cool as Bangalore.

TANK SYSTEM OF BANGALORE CITY

Interconnected tanks were made possible by the area's undulating geography, which ranged in altitude from roughly 600 m to about 962 m AMSL. Due to the abundance of lakes (approximately 285 tanks in a 161 sq km area, Bangalore's spatial extent , the city was once rightly referred to as the "city of Lakes." To permit the transfer of excess water to the following lake, these tanks were all connected by canals and drains (kaluveys). These tanks served the region's fundamental requirements, including supporting food production (fish, etc.) and agricultural activity. They also provided drinking water for the community and habitat for fish and other aquatic ecosystems.
In a city like Bengaluru, which lacks a perpetual river and is dependent on several tanks for both water supply and leisure, tanks are particularly crucial. On the city's uneven landscape, several tanks have been built over many years. Its geography makes it easier to use the tanks since it made it possible to create a chain of tanks that feed into one another and provide enough water. Tanks are beneficial for recharging groundwater as well. 

Fig. 4: Bengaluru's Lakes connectivity

VALLEY SYSTEM OF BANGALORE CITY

Fig. 5: Bangaluru’s major Valleys

Kormangala-Challaghatta Bangalore, which is situated on a ridge, has three valleys that serve as watersheds: the Koramangala Challaghatta Valley (K&C Valley), the Hebbal Valley (H Valley), and the Vrishabhavati Valley (V Valley). K&C valley, which spans an area of 255 square kilometres inside the boundaries of Bruhat Bengaluru, is the biggest, followed by Hebbal valley (207 square kilometres), and Vrishabhavati valley (165 square kilometres). While Vrishabhavati Valley enters the Arkavathi River, a tributary of the Cauvery River, both K&C Valley and Hebbal Valley unite at Nagondanahalli Village and run on to the Dakshina Pinakini River.

Through its tributaries Arkavathi, Pinakini or Pennar, and Shimsha, Bangalore's drainage system transports water to the River Cauvery. The region's centre, north, and east are undulating, with tracts of highland covered in scrub and a series of tanks created by enclosing streams in the valleys in the low areas. Small ponds and huge tanks of various sizes may be found in these valleys. The land's southern region is made up of closely spaced hills that are encircled by dense rainforests.

Valley houses many tanks and play a very important role in its hydrological processes. Thus, in each of the three valley systems, the tanks create a chain of reservoirs. Small streams are born in each valley near the ridge's summit. In three valleys, they cascade to create significant stream networks. The tanks in Bangalore are therefore stored in the valleys, and the tanks are connected to one another by a network of chains, creating a cascade effect across the entire system.

WATER STREAM CONNECTING LAKES/TANKS

Stream ordering is a method of assigning a numeric order to links in a stream network. This order is a method for identifying and classifying types of streams based on their numbers of tributaries. Some characteristics of streams can be inferred by simply knowing their order.

The highest stream order is sixth order in the Vrishabhavathi Valley basin, whereas the highest stream order in the other two Valleys is fifth order. It was found that the valley systems created a dendritic drainage pattern. 

The Vrishabhavathi Valley is elongated in shape, but the K-C Valley and the Hebbal Valleys are less elongated in shape, according to the watershed shape factor.

The drainage density of the three Valleys showed that they are classified as having coarse drainage density. The three Valleys' relief features provide modest reliefs that suggest a flat terrain

 

Fig. 6:  Bangalore's water stream map, with the fourth-highest stream order and the first-lowest stream order

The above study provides a possibility to work further on several Bangalore lake series depending on their stream order.

- Composed by: Chidambari Kulkarni