Understanding Our Rivers

City planning in most cities is based on the traditional Euclidean form of zoning where similar land uses are grouped close to one another regardless of physical conditions.

However, with changing climate and declining natural ecologies more innovative and inclusive approaches need to be adopted. Urban spaces, when juxtaposed with naturally existing systems (mangrove forests, wetlands, rivers, creeks), reveal some processes to address these issues and create liveable ecologies. Suggesting land uses and designing development policies based on watershed features is one such idea especially for cities like Mumbai that have a volatile relationship with water. This research analyses riverine corridors in Mumbai that have been ignored behind tall perimeter walls and squeezed between dense, unregulated informal settlements and factories.

Despite their unhealthy state, the corridors have the potential to become some of Mumbai’s most pleasant spaces. 

The city’s rivers are seasonal and begin in the catchment areas in the hills of Borivali National Park and flow via the wetlands into the Arabian Sea: Dahisar in the north, Oshiwara towards the west, Poisar in the center and Mithi in the southern part of Mumbai.

In this research, Oshiwara River’s urban corridor is used to illustrate this framework. The river flows westward through dense informal settlements, dye-making industries, gated residential communities and mangrove forests on its way to the Arabian Sea. Presently, there are negative perceptions due to river bed and water pollution, regular floods and unpleasant conditions along the river’s edge.

Juxtaposing these issues with physical conditions of the riverine corridor through hydrological analysis of the watershed area presents valuable intervention opportunities for revitalizing the corridor. Such a process, though seemingly intuitive, is not common. The framework I propose, comprises of using combinations of some of the best practices and policies encouraging public participation and empowerment.

For Oshiwara River’s urban corridor, these are some potential intervention alternatives:

1. Improving storm water drainage infrastructure along the development corridor and sea level rise resilient strategies using a decentralized approach.

This proposal entails designing a system based on best management practices (BMPs) for storm water drainage design and management from across the world. In contrast to the present centralized system where storm water from all over the city is collected and then released untreated into the Arabian Sea, this intervention proposes a decentralized approach. The image below illustrates how this proposal would function at the neighborhood block scale.

In order to convert this concept into a realistic proposal, the site is divided into 28 sub-watersheds defined by neighborhood blocks.

This decentralized approach will not only help detain and treat surface runoff water until the tide subsides but will also help recycle water for non-potable purposes, thus easing the load on water supply infrastructure. Additionally, sensitively designing the detention basins, treatment planters and wetland swales could potentially create a livable environment in the development corridor.

The Government also has the potential to set a precedent for the rest of the city. Most of the land South of River Oshiwara between Link Road and SV Road is zoned as Special Planned Area and owned by the MMRDA (Mumbai Metropolitan Region Development Authority.)

They have plans to create an Oshiwara Business District there. However, the Global Sea Level Rise map suggests that a major part of this area would be under water in 36 years and most of the rest of it in another 50 The MMRDA could use this as an opportunity to propose sea level rise resilient designs by surrendering land to the river and building a combination of horizontal and vertical levees by planting wetlands and mangrove forests along the river’s edge.

2. River and riverfront restoration through public empowerment and participation.

This intervention emphasizes an inclusionary approach through public-private partnership based on public outreach measures undertaken during the design development process and how opinions of locals, experts and developers can be accommodated.

Residential buildings line the riverfront along the river’s development corridor. If awareness of the benefits of river and riverfront restoration can be spread among the residents it could catalyze the formation of public interest and opinion. However, approximately 20 of the land fronting the river has informal settlements living and working on it. Hence, municipal action would be required to set regulations not only to treat effluents but also to allow environmentally sensitive use of land along the riverfront. This could be furthered by making the Coastal Regulation Pone norms flexible according to local conditions, making the area more beneficial for residents, developers and the natural systems.

Awareness of benefits of living along riverine ecologies can be spread through surveys and informative leaflets. In order to better understand the relationships and interactions between people who live and traverse this corridor, it is important to learn about the people’s and the municipality’s perception of the river corridor. People’s perception can be studied through such questions:

•Perception of neighborhood: Which part of the corridor do the residents consider as their neighborhood does this include the river?

•Daily exposure to the river: how often does the residents and passersby cross the river or see it?

•Awareness of ecological benefits of the river: Have they experienced floods in their neighborhood? Is there any awareness or worry about climate change and sea level rise?

•Sense of community : Do their friends or family live in their demarcated neighbourhood5 Municipal perception can be looked at in the following ways

Terminology used to define urban rivers: Why is it referred to as a ‘nullah’ in some documents and ‘river’ in others? What effect does this definition have on their maintenance of rivers?

Responses to these questions would help reveal the extent to which residents and passersby are aware of the river and its benefits. Additionally, information about vulnerability of the corridor to Floods and sea level rise could be distributed to spread awareness.

Here, the government agencies become facilitators and can mediate the process ensuring its inclusiveness. This need to spread public awareness and involve the local population in the decision-making process is most essential to address many issues around deterioration of riverine ecologies. For example, the importance of improving storm water drainage infrastructure and proposing sea level rise resilient strategies along the urban corridor and to illustrate the need to integrate the site’s physiology with land use.

Thus, a two-pronged approach of upgrading infrastructure sensitively and utilizing local knowledge are most relevant to maximize the potentials provided by Mumbai’s rivers. Many of these design strategies could help create not only more livable and pleasant public spaces but also enrich our lives.