Wetlands and rivers: Restoration and management

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Moderator of this session: Guy Alaerts (Professor of Knowledge and Capacity Management for the Water Sector at UNESCO-IHE)

This session will include the speakers: Rajiv Ranjan Mishra (Director General
National Mission For Clean Ganga (NMCG), Ministry Of Jal Shakti, Government Of India), Kalpana Maraj (Masters student in Chemical Engineering at the University of Cape Town) and Praveena Sridhar (Coordinates the Cauvery Calling project)

Take a look at the abstracts below!

Making Ganga Basin Cities Risk and Climate Resilient

Presenting author: Rajiv Ranjan Mishra (Director General National Mission For Clean Ganga (NMCG), Ministry Of Jal Shakti, Government Of India)

The adverse impact of climate change on water includes less predictable water availability, increased flooding incidences, storm surges and rising case of sea levels which further leads to destruction of water points and sanitation services and contaminates the water sources. In some regions, the droughts are worsening the issue of water scarcity and impacting 40% of world’s population in many ways. It is a difficult task to protect and conserve the water quality and quantity, but also provides an opportunity to use water as a leverage for improving ecosystems, economy, agricultural productions, and tackle inequality leading to achieving various Sustainable Development Goals. In India, the Ganga River Basin is the largest river basin, covering around 26% of country’s land area, hosting about 43% of India’s population(around 520 million)and contributing 28% of India’s water resources.The Government of India has brought in a long-term perspective with a proper institutional framework and created an integrated mission named National Mission for Clean Ganga (NMCG) for protection, conservation, and rejuvenation of River Ganga. NMCG is guided by a holistic approach with focus on riverine ecosystem including municipal sewage, industrial effluents, municipal solid waste, non-point sources of pollution and interventions for improving ecological flows, biodiversity conservation, afforestation, improving amenities and sanitation at river banks, capacity building, research & monitoring and public awareness.At NMCG, along with implementing pollution abatement measures and creating sewerage infrastructure by various innovative practices such as Hybrid Annuity Mode and One City One Operator models, an equal emphasis has also been laid for the holistic development of the Ganga river basin. Moreover, NMCG has closely followed the global best practices which are similar toWater as Leverage (WaL)and Room for Rivers rolled out by the Government of Netherlands in developing the holistic river management plan. Consequently, it has collaborated with various stakeholders and strived to make the Ganga basin cities adaptive and resilient by making them river and water sensitive. For instance, a dedicated framework for Urban River Management Plans has been developed which enables city managers to strategize and develop river sensitive master plans for their cities. Likewise, we are also working on encouraging the city managers to transform their cities to include water sensitive urban design and planning. A recent study by NMCG showed how allocating a mere 2-3% of the existing open spaces and parks has the potential to harvest over 2600 million liters of stormwater runoff. NMCG is also currently underway to launch a unique initiative of River City Alliance to provide a platform for river cities to develop partnership for sustainable river centric planning and development.To conclude, NMCG seeks to present the unique challenges and solutions devised to make the Ganga basin cities risk and climate resilient by primarily adopting a holistic vision wherein all streams of water, i.e. groundwater, surface water and stormwater as well as water bodies like wetlands, lakes, etc. are considered as an integrated water system. Today, cities need to learn how to live with rivers, build with nature and make room for rivers, and NMCG through its work wants to precisely share this with the world.

Cauvery Calling – A blueprint for the tropical world

Presenting author: Praveena Sridhar

Expert bodies such as the UN Convention to CombatDesertification (UNCCD) have arrived at the understanding that massive afforestation is the single-most effective solution for present water, soil and livelihood issues. The UN Environment Program (UNEP)directives ‘a Trillion Trees’, and the BonnChallenge all point to this same scientific solution.Cauvery Calling aims to execute this vision.The world’s largest farmer-driven ecological movement- ‘Cauvery Calling’ is a blueprint for the tropical world. Marrying ecology and economy, the initiative aims to revitalise the severely depleted Cauvery river, and address the dire economic concerns of the populace around the Cauvery River basin – 84million people and an economy propelled by 5.2 million farmers in the Indian states of Tamil Nadu andKarnataka.Cauvery Calling aims to enable 5.2 million farmers to plant 2.42 billion trees along the Cauvery river basin(83,000 square kilometers) in the next 12 years. By shifting the farmers to tree-based agriculture, it seeks to bring one-third of the basin under tree cover.In heavily populated countries like India, where approximately 80% of available land is owned by farmers, their involvement is vital.Project benefits:•Revitalizing the river and groundwater levels by increasing water retention in the Cauvery basin by an estimated 40% of Cauvery’s annual flow.• Augmenting farmer income through agroforestry. Many have already seen their incomes rise by300-800%.• Replenishing the soil’s nutrients and carbon content whilst providing food security for the region.• Increasing the green cover of the Cauvery Bas into the national aspiration of 33%, protecting biodiversity, reducing the carbon footprint and enhancing the climate resilience of the region.• Sequestering 207-307 million tons of CO2, equivalent to 8-12% of India’s NDC for 2030 under the ParisAgreement.• Establishing a large-scale, proven model for river revitalization, soil restoration and farmer upliftment that is replicable in most parts of the tropical and subtropical world.An estimated 9-12 trillion liters of water will be sequestered in the basin – improving the ground water situation and Cauvery’s flow. While most water-related environmental projects focus on equitable or more efficient usage of available water, Cauvery Calling strives to augment water availability. Leaves, branches and similar tree litter will help restore degraded soils and improve soil carbon content. As per financial estimates by the UN Convention to Combat Desertification and land degradation estimates by the GlobalEnvironment Facility, every square kilometer of restored land can save $12,800 each year.Cauvery Calling has so far enabled 107,000 farmers to shift to agroforestry and has planted 52 million trees. Isha Foundation is a non-profit human-service organisation, with human well-being as its core commitment. The foundation has been accredited by the UN Convention to Combat Desertification(UNCCD), being accepted to its Convention of Parties(COP) at New Delhi in 2019. In 2020, Isha Foundation was accredited to the UN Environmental Programme (UNEP) for its outreach efforts.

Assessing the suitability of constructed wetlands to treat surface water runoff from informal settlements in South Africa

Presenting author: Kalpana Maraj (mrjkal001@myuct.ac.za)

Institution: Future Water Institute, University of Cape Town

Polluted runoff from densely populated and poorly serviced informal settlements is a persistent issue in South Africa resulting in environmental degradation and health risks.The treatment and potential reuse of surface water runoff from informal settlements is challenging due to the elevated nutrient (NH3, NO2-, NO3-and PO43-) concentration sand other contaminants. More than 4 million people currently live in informal settlements in South Africa and this number is expected to grow which will result in further catchment degradation. In developed areas, runoff is channelled into sewer systems and is treated via a city or municipality’s stormwater management plan. This is not the case for informal settlements where the polluted runoff is discharged into rivers and other nearby water bodies without treatment.A decentralised, non-invasive and easy to maintain surface water rehabilitation system is a consideration especially if multiple benefits can be derived from the treated runoff that can be used in a local setting.A major benefit that has been identified is the use of treated runoff for agricultural purposes in peri-urban areas. Engineered nature-based solutions such as constructed wetlands (CWs) are a well-known remediation measure that are cost-effective, scalable and easy to maintain.However, fluctuating nutrient levels in surface runoff from informal settlements pose a challenge to achieving consistent nutrient reduction in a system. The aim of this study was to assess the extent of nutrient degradation that could be achieved by using CWs for treating polluted runoff from informal settlements.This was done by assessing whether the extent of nutrient degradation could be maintained despite the highly variable water quality.The nutrient degradation potential of amicrobially colonised pilot scale horizontally orientated subsurface flow CW(length: 2 m; width: 0.44 m; depth: 0.7 m),packed with stones of 8-11 mm in diameter, was assessed.Surface runoff into the Stiebeuel River,near Franschhoek in the Western Cape, was collected and used in six nutrient degradation studies with varying flow rates of 0.5 L/min and 1.5L/min. Each batch study was conducted over 228hours whereby 200 L of aerated contaminated water was circulated through the system during the study. NH3 reductions of 70.6% -91.8% and PO43-reductions of 74.7%-88.3% were observed.The mechanism of nitrogen removal was biological while phosphorus removal occurred through physical (adsorption) and biological means. The main biological processes occurring in the pilot CW were nitrification and denitrification with up to 64% denitrification achieved in the system after 228hours. Nitrification occurred from 0-60 hours at 1.5 L/min and from 0-72 hours at 0.5 L/min. Denitrification occurred from 144 -228 hours at 1.5 L/min and 168 -228 hours at 0.5 L/min.It is evident that the pilot scaleCW did not achieve a consistent extent of nutrient uptake in each nutrient degradation study but that the biological processes were consistent. Further studies on the effects of retention time and dissolved oxygen concentrations on CW performance could yield greater nutrient degradation efficiencies with treated runoff being fit to reuse for agricultural purposes.

CWwere nitrification and denitrification with up to 64% denitrification achieved in the system after 228hours. Nitrification occurredfrom 0-60 hours at 1.5 L/min and from 0-72 hours at 0.5 L/min. Denitrification occurred from 144 -228 hours at 1.5 L/min and 168 -228 hours at 0.5 L/min.It is evident that thepilot scaleCW did not achieve a consistent extent of nutrient uptake in each nutrient degradation study but thatthe biological processes were consistent. Further studies on the effectsof retention timeand dissolved oxygen concentrationson CW performance could yield greater nutrient degradation efficiencieswithtreated runoffbeing fit to reuse for agricultural purposes. Key words: Nutrient degradation;constructed wetlands;informal settlements; nitrification;denitrificatio

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