ENVGEO362 lecture 4 Fall 2024.pdf

Natural resource management 4. Water resource management Some important legislation, stormwater management Main source: – Textbook chapter 14 – Additional sources: see sources mentioned on slides Some important legislation ref. water governance Water Resources Act (Ontario, 1990) Purpose: provid...

Natural resource management 4. Water resource management Some important legislation, stormwater management Main source: – Textbook chapter 14 – Additional sources: see sources mentioned on slides Some important legislation ref. water governance Water Resources Act (Ontario, 1990) Purpose: provide for the conservation, protection and management of Ontario’s waters and for their efficient and sustainable use - focuses on both groundwater and surface water in Ontario - regulates sewage disposal and “sewage works” - prohibits the discharge of polluting materials that may impair water quality - regulates permits to take more than 50,000 liters of water per day from ground or surface water sources (see case study 4) - regulates well construction, operation and abandonment in addition to the approval, construction and operation of “water works” Source: https://www.ontario.ca/laws/statute/90o40 Some important legislation ref. water governance Environmental Protection Act (federal, 1999) An Act respecting pollution prevention and the protection of the environment and human health in order to contribute to sustainable development - prohibits discharge of any contaminants into the environment that cause or are likely to cause adverse effects. - amounts of approved contaminants must not exceed limits prescribed by the regulations. - requires that spills of pollutants are reported and cleaned up. - has the authority to establish liability on the party at fault; imposes a duty on corporate officers and directors to take all reasonable care to prevent the corporation from causing or permitting unlawful discharges of contaminants into the natural environment. Source: https://lois-laws.justice.gc.ca/eng/acts/C-15.31/ Some important legislation ref. water governance Safe Drinking Water Act (Ontario, 2002) Purposes: recognize that the people of Ontario are entitled to expect their drinking water to be safe; provide for the protection of human health and the prevention of drinking water health hazards through the control and regulation of drinking water systems and drinking water testing. - initiated by the inquiry into the Walkerton tragedy in 2000 (also: the 2006 Clean Water Act) - all municipal drinking water systems must obtain an approval from the Director of the Ministry of the Environment in order to operate, - operators must be trained and certified to provincial standards. - provides a framework for testing with legally-binding standards for contaminants in drinking water, and the mandatory use of licensed and accredited laboratories for drinking water testing Source: https://www.ontario.ca/laws/statute/02s32 Some important legislation ref. water governance Clean Water Act (Ontario, 2006): Purpose: protect existing and future sources of drinking water. - Ontario has a multi-barrier approach to protect drinking water; the first step (source water protection) is protecting the surface or groundwater that supplies drinking water systems. - ensures communities protect their drinking water supplies through prevention – by developing collaborative, watershed-based source protection plans that are locally driven and based on science. - establish source protection areas; and a local multi-stakeholder source protection committee for each area; identifying significant existing and future risks to their municipal drinking water sources, and develop plans to address these risks. Source: https://www.ontario.ca/laws/statute/06c22 Multi Barrier Approach for drinking water in Ontario 1. Source Water Protection: Ontario’s Clean Water Act helps protect sources (lakes, rivers, groundwater) for municipal drinking water systems from contamination and depletion. 2. Water Treatment System: The source water must be treated so that any harmful contaminants and organisms are reduced or removed. 3. Inspection: Ontario carries out inspections of municipal residential drinking water systems (based on the Safe Drinking Water Act) Multi Barrier Approach for drinking water in Ontario 4. Testing: Trained and certified operators regularly test municipal residential drinking water. 5. Distribution: Municipalities make sure that there is disinfectant in the distribution system (pipes, pumping stations, …), and test it regularly. See e.g. https://www.hamilton.ca/home- neighbourhood/water-wastewater- stormwater/water-treatment-distribution/ drinking-water-system Some important legislation ref. water governance On the municipal level (example): Hamilton’s Sewer Use By-law 14-090 regulates the discharge of water and wastewater that enters the City’s sanitary, combined and storm sewers by: – Establishing limits for common pollutants – Establishing a list of prohibited substances – Identifying requirements that users have to meet in order to discharge – Enabling the City to monitor and reduce the impact of spills – Enabling the City to monitor and control discharges E.g. the City may enter any industrial, commercial, or institutional property at reasonable times to inspect the discharge of any matter into the sewer works, and conduct tests and take samples. Source: https://www.hamilton.ca/build-invest-grow/operating-business/commercial-water-sew er/sewer-use-by-law Impacts of urbanization on the hydrological cycle 1) Increase in direct runoff; decrease in infiltration and evapotranspiration Consequences: – increase in magnitude (incl. velocity increase during storms) and frequency of runoff events. – soil moisture replenishment and groundwater recharge are reduced (due to a decrease in infiltration), affecting groundwater sources which are important as a resource, but are also important in adding to the base flow of streams to sustain aquatic life. Impacts of urbanization on the hydrological cycle 2) Changes in stream response to storm events: – increased peak streamflows, also – more rapid stream response Summer floods resulting from high intensity thunderstorms are more common in urban areas. Flood Hydrographs for Urbanized and Natural Drainage Basins (Watt et al, 1989) Impacts of urbanization on the hydrological cycle 3) Changes in stream morphology: e.g. increased stream cross-sectional area, downcutting of the stream channel, increased sediment loads, changes in location and meander pattern, … Impacts of urbanization on the hydrological cycle 4) Changes in aquatic habitat and ecology: due to stresses because of extreme shifts in hydrology, geomorphology, and water quality: – more algal organic matter, – a decline in aquatic habitat quality and diversity in the fish, plant, animal and aquatic insect communities in the stream; – loss of sensitive coldwater species; – destruction of freshwater wetlands, riparian buffers and springs; – a decline in wetland plant and animal community diversity. Impacts of urbanization on the hydrological cycle 5) Changes to water quality: the washing off of accumulated deposits from impervious areas during storms is the dominant source of contaminants (especially with advanced urbanization). – Urban stormwater runoff may contain elevated levels of suspended solids, nutrients, bacteria, heavy metals, oil and grease, and pesticides, as well as sodium and chloride from roadsalt. Impacts of urbanization on the hydrological cycle 5) Changes to water quality (continued) – Increased turbidity (more murky, cloudy water) interferes with photosynthetic activity by reducing light penetration. – Solids in suspension may clog gills and interfere with fish feeding, and the deposition of sediment may cover spawning areas and smother benthic (i.e. occurring on/associated with the bottom of a body of water) communities. – Organic matter exerts an oxygen demand (e.g. because microbes use oxygen to break down this organic matter) and may severely depress the levels of dissolved oxygen in the receiving water. Goals of stormwater management Multiple goals (because urbanization affects the hydrological cycle in multiple ways): 1. prevent an increased risk of flooding (e.g. in urban areas with increased runoff) 2. maintain the natural hydrologic cycle – maintain soil moisture to sustain vegetation, – maintain groundwater recharge for water supply in certain areas – maintain the base flow of streams 3. prevent stream erosion (and try to avoid degradation of stream habitat and biodiversity) 4. protect water quality Source: https://www.ontario.ca/document/stormwater-management-planning- and-design-manual-0#section-2 How to achieve stormwater management goals? Aiming for these stormwater management goals means working at different levels: 1. integrate land use planning and environmental planning e.g. preventive approach through site design of communities to reduce stormwater runoff generation 2. pollution prevention to prevent contamination of stormwater e.g. reduced vehicle use, proper disposal of pet feces and litter, avoid excessive use of road salt and de-icers, … 3. protecting natural areas e.g. forested areas reduce and delay stormwater runoff by intercepting and storing precipitation, wetlands store and slow flood water and enhance water quality,... How to achieve stormwater management goals? 4. “treatment train”: series of practices that meets stormwater management objectives for an area, e.g. a combination of lot level control, conveyance control, and end-of-pipe control 4a. controls at the lot level: infiltration controls to promote infiltration at the lot level; designs to temporarily store stormwater runoff and release it at a controlled rate E.g. Infiltration trenches (several lots) – soakaway pits (individual lots) cvc.ca/wp-content/uploads/2012/02/lid-swm-guide-apdxa-soakaways-infiltration-tr enches-chambers.pdf How to achieve stormwater management goals? 4. “treatment train”: 4b. conveyance system controls: at the level of the conveyance system E.g. (Enhanced) grassed swales (designs to temporarily store stormwater runoff and then let in infiltrate into the ground) cvc.ca/wp-content/uploads/2012/02/lid-swm-guide-apdxa-enhanced-grass-swales.pdf E.g. Pervious pipe systems (perforated – to allow water to flow out - downstream conveying pipe in a bed of stones, ultimately letting the water infiltrate into surrounding soils. cvc.ca/wp-content/uploads/2012/02/lid-swm-guide-apdxa-perforated-pipe-system s.pdf How to achieve stormwater management goals? 4. “treatment train”: 4c. end-of-pipe control facilities: receive stormwater runoff from a conveyance system and discharge it to receiving waters Dry ponds Detention basin to temporarily store collected stormwater runoff and release it at a controlled rate. No permanent pool of water in the main basin, so not performing as well as wet ponds for water quality control. Wet ponds Later ponds, designed to provide both water quantity and quality control, are typically larger and support a permanent pool with active storage. The added storage allows more time for sediment and associated contaminants to settle out as water is gradually released to nearby streams. How to achieve stormwater management goals? Some problems with stormwater ponds Since the 1980s, stormwater ponds became part of new developments, in order to deal with increasing peak flows. They also help remove total suspended solids. However, * Ponds are often neglected or not maintained at a rate to ensure proper performance; due to the high cost for cleaning out these ponds), according to a 2016 article in watercanada.net CAD 250- 500K per pond, and Hamilton e.g. has ± 120 ponds... * In terms of water quality, with the rise of stormwater ponds, comes increases in temperature and nutrient output. * Stormwater ponds alone don’t reduce stormwater volumes (in comparison to e.g. LID which tries to manage rain where it falls), resulting in increased pressure on streams. Stormwater ponds only reduce the rate, not the volume of stormwater runoff entering watercourses. Time for a short online GIS investigation of some water and stormwater infrastructure in Hamilton Use the document “case study lecture 4” on Discovery. The sewer system in an older city like Hamilton separated sewer system: – in newer parts of Hamilton – sanitary sewer: carries sewage; takes it to the wastewater treatment plant – storm sewer: collects and carries storm water which enters outdoor drains such as downspouts and catch basins; and release the water they collect directly to the environment. – during rain events a lot of the stormwater in the newer parts of Hamilton temporarily ends up in stormwater ponds. Source: https://www.hamilton.ca/home- neighbourhood/water-wastewater-stormwater/ wastewater-collection-treatment/sewer-systems The sewer system in an older city like Hamilton combined sewers: – in older parts of Hamilton – one pipe collects both the wastewater from homes and businesses, and stormwater from rain or melted snow. – the combined wastewater/stormwater is sent to the wastewater treatment plant where it is cleaned and released into Hamilton Harbour. – cfr. stormwater ponds temporarily holding up excess stormwater, the older combined sewer system needed a similar system to temporarily hold the excess diluted wastewater; in the last decades, Hamilton built a few large “combined sewer overflow tanks”, which can hold 300,000+ m3. The sewer system in an older city like Hamilton – When the storm stops, and the sewer system and treatment plant have capacity for the volume of wastewater inside the combined sewer overflow tanks, the water is then put back into the sewer system to head to the treatment plant for cleaning. That is, if all works as normal… – However, there is also an overflow option in case the tanks are full during intense rain events; then the excess diluted wastewater is released directly in the harbour …; follow the monitoring of wastewater overflows and bypasses online via https://www.hamilton.ca/home-neighbourhood/water-wastewater- stormwater/wastewater-collection-treatment/monitoring And there has been at least one instance of a very significant prolonged spill over multiple years (Chedoke Creek Spill) at https://www.cbc.ca/news/canada/hamilton/chedoke-creek-spill-guilty-plea-fine-1.6912880 Achieving stormwater management goals: LID Low Impact Development is “a next step” in stormwater management: decentralized micro-controls (e.g. bioswales, rain gardens, permeable pavement, green roofs…) for runoff prevention and stormwater treatment, instead of a reliance on centralized end- of-pipe facilities. A little preview via Climate Change Solutions – LID (Credit Valley Conservation) https://www.youtube.com/watch?v=GRy4meGG7JU Principles: 1. focus on runoff prevention 2. treat stormwater as close to the source area as possible 3. use existing natural systems as framework for planning 4. create multifunctional landscapes 5. educate and maintain To be investigated more in detail during the excursion (including the report assignment). Achieving stormwater management goals: LID Important notes: – The adaptive environmental management (AEM) cycle identifies monitoring as a key element in the knowledge building and learning process of stormwater management systems, including LID. https:// cvc.ca/wp- content/ uploads/ 2012/10/ aem-cycle- web.jpg – Similar types of green infrastructure are now implemented (with different names), e.g. “sponge parks” in Montreal, see https://www.youtube.com/watch?v=NxBbojaBGeM