Author: Caleb Spyksma

Along with changes in the presence and absence of water, the intertidal zone is characterized by shifts in salinity, temperature, and movement.  

Salinity: Evaporation of water at the upper intertidal zone increasing the salinity, while precipitation inversely decreases it¹.  

Temperature: The regulating effect of water on temperature influences the habitability of the intertidal zone.  While low intertidal zone organisms benefit from more consistent inundation and tend to be more sensitive to temperature change (eg, coral reefs) organisms in the high intertidal zone must be especially resilient to temperature swings.  in coastal British Columbia in 2021, very low tides and a record breaking heat wave coincided, causing mass die-offs of intertidal species due to temperature and increased rates of evaporation². 

Movement:  the mechanics of water in currents and wave action influence the habitability of in intertidal area.  While some organisms such as eel grass and sand dollars grow best in sheltered locations, other organisms such as Chiton and Green anemones thrive where wave action is the strongest³.  Water movement in the form of tidal fluctuation dramatically influences biodiversity. On some rocky coastlines, stratified layers of biological communities at different tidal levels can be easily visible, while in mudflats and tidal marshes, these layers may occur below the sand and out of site⁴.  Currents and wave action are also the primary source of life in the intertidal zone, refreshing the water with food, regulating temperature, and clearing away harmful contaminants.  

Figure 1: Example of a Temperate Rocky Shoreline Intertidal Zone

[1] Geng, Boufadel, and Jackson, “Evidence of Salt Accumulation in Beach Intertidal Zone Due to Evaporation.”

[2] Migdal, “More than a Billion Seashore Animals May Have Cooked to Death in B.C. Heat Wave…”

[3] DiNenno, “On the Edge.”

[4] “Biodiversity on Rocky Coasts.”

Intertidal zones house a variety of plant and animal species that are specifically suited to this somewhat inhospitable environment, which in turn act as food for both off-shore aquatic animals and on-shore mammals and birds: a critical nutrient pathway between the sea and the land that is exemplified by the impacts of intertidal herring spawning in the North Pacific and its impact on terrestrial ecosystems¹.  

The intertidal zone also serves as natural shoreline protection, regulating and shaping erosion, influencing saltwater incursion and inundation, and protecting low-lying areas from flooding in extreme weather events².

Beyond the above ecosystem services, intertidal zones are often the gateway for the general public to experience and interact with marine ecosystems in a positive and educational way. The multisensorial experience of exploring tidepools and wading at the waters edge cultivates wonder and appreciation for the richness that lies below the high-tide line.

[1] Walters, “Protecting (Marine) Subsidies.”

[2] “Intertidal Zone.”

Massive environmental change and degradation has been wrought in and around our coastal cities.  Intertidal ecosystems are constantly under threat from development of housing, infrastructure, and industry – Many of our coastal cities are built on artificial land extending beyond the historic shoreline.  Robbed of natural protection from waves and erosion, the new shoreline requires significant protective measures, further degrading habitat and costing significant sums in installation and maintenance.  The water in these intertidal zones is prone to contamination from run-off, sewage, and industry, causing heavy-metal buildup and algal blooms that ravage delicate ecological balance and dramatically reduce biodiversity.  Because the intertidal zone links terrestrial and aquatic ecosystems, the effects of this degradation extend far beyond the intertidal zone. Knowledge of this has prompted environmental designers to develop new ways of revitalizing and regenerating our urban intertidal zones across scales in ways that aim to integrate ecology and the resulting ecosystem services into our urban fabric.

Even non-urban coastlines are at risk from pollution, resource extraction, infrastructure, global warming and sea level rise (refer to Water Quality and Sea Level Rise for further information). Understanding the history of a coastline and any interventions that have occurred is critical at the outset of any project within the intertidal zone.

Figure 2 (left): ECOncrete’s tidepool creations at installation. Designboom.

Figure 3 (right): ECOncrete’s tidepool creations after colonization by intertidal species. ECOncrete.

With the ongoing and increasing threat of climate change impacts in the form of sea level rise and intense storm surges, intertidal zones are seen by many as the front-lines in a battle against nature. Environmental designers, equipped with an understanding of of the intertidal zone, are in a critical position to work with nature and the changing climate, rather than against it, in order to keep people and ecosystems safe. In parallel to the nature-based solutions to rainwater management presented in LID (see the Rainwater Management blog page), nature based solutions to urban intertidal conditions is a way forward that shows great promise. This can manifest in engineered solutions such as ECOncrete’s shoreline protection products that provide habitat for intertidal life1, as naturalized shoreline interventions such as Mithun’s Sea2City competition entry in False Creek, Vancouver, or as combined naturalized and engineered projects such as SCAPE’s well-known “Oystertexture” proposal for New York City3. Along with the environmental designer(s)’s extensive site-specific research, Interventions within the intertidal zone should involve ecologists, biologists and geotechnical engineers that are experts in local intertidal zone specifics: what may work in one location may be harmful in another.

DiNenno, Natalie. “On the Edge: The Curious Lives of Intertidal Organisms and How We Monitor Them.” U.S. National Park Service, 2022. https://www.nps.gov/articles/000/on-the-edge-the-curious-lives-of-intertidal-organisms-and-how-we-monitor-them.htm.

ECOncrete. “Shoreline Protection.” https://econcretetech.com/applications/shoreline-protection/.

Encyclopedia of the Environment. “Biodiversity on Rocky Coasts: Zoning and Ecological Relationships,” May 29, 2017. https://www.encyclopedie-environnement.org/en/life/biodiversity-on-rocky-coasts-zoning-and-ecological-relationships/.

Geng, Xiaolong, Michel C. Boufadel, and Nancy L. Jackson. “Evidence of Salt Accumulation in Beach Intertidal Zone Due to Evaporation.” Scientific Reports 6 (August 11, 2016): 31486. https://doi.org/10.1038/srep31486.

Migdal, Alex “More than a Billion Seashore Animals May Have Cooked to Death in B.C. Heat Wave, Says UBC Researcher | CBC News.” CBC, July 5, 2021. https://www.cbc.ca/news/canada/british-columbia/intertidal-animals-ubc-research-1.6090774.

Mithun. “Sea2City Design Challenge.” https://mithun.com/project/sea2city-design-challenge/.

National Geographic Education. “Intertidal Zone.” https://education.nationalgeographic.org/resource/intertidal-zone.

SCAPE. “Oyster-Tecture.” https://www.scapestudio.com/projects/oyster-tecture/.

Walters, Kristen. “Protecting (Marine) Subsidies: Nutrient Flows from Ocean to Land.” Raincoast Conservation Foundation, May 29, 2018. https://www.raincoast.org/2018/05/protecting-marine-subsidies-nutrient-flows-from-ocean-to-land/.

Images

Figure 1: Author’s work

Figure 2: Designboom, Lea Zeitoun. “ECOncrete® Blocks Are Bio-Enhanced Materials for Sustainable Marine Construction.” designboom | architecture & design magazine, February 9, 2022. https://www.designboom.com/technology/econcrete-coastalock-bio-enhanced-material-marine-construction-02-09-2022/.

Figure 3: ECOncrete. “Our Technology.” https://econcretetech.com/econcrete-technology/.

“Explore the Rocky Shore and Stanley Park.” Vancouver Natural History Society, 2009. https://naturevancouver.ca/wp-content/uploads/2018/12/Nature_Vancouver_Intertidal_Pamphlet.pdf.

Field guides and similar documents can be very helpful when designing for specific organisms and communities of organisms in the intertidal zone, as they often include information on habitat and relationships between species. This example is focused on the rocky shore of Stanley Park, Vancouver.

Thom, Ronald M., Heida L. Diefenderfer, John Vavrinec, and Amy B. Borde. “Restoring Resiliency: Case Studies from Pacific Northwest Estuarine Eelgrass (Zostera Marina L.) Ecosystems.” Estuaries and Coasts 35, no. 1 (January 1, 2012): 78–91. https://doi.org/10.1007/s12237-011-9430-6.

Eelgrass meadows are an important intertidal and subtidal ecosystem not covered significantly in this blog post. This research article is a helpful resource for those specifically interested in this.

Valiela, Ivan, Marci L. Cole, James Mcclelland, Jennifer Hauxwell, Just Cebrian, and Samantha B. Joye. “Role of Salt Marshes as Part of Coastal Landscapes.” In Concepts and Controversies in Tidal Marsh Ecology, edited by Michael P. Weinstein and Daniel A. Kreeger, 23–36. Dordrecht: Springer Netherlands, 2000. https://doi.org/10.1007/0-306-47534-0_3.

Access this article for further information on salt marshes, a critical intertidal ecosystem.

Raffaelli, David, and Stephen Hawkins. Intertidal Ecology. Springer Science & Business Media, 1996. https://link.springer.com/book/10.1007/978-94-009-1489-6.

This book is a helpful overview resource on intertidal ecology.

In the face of sea level rise and other climate change impacts, Oyster-tecture imagines working with the constructive nature of oysters to calm wave action, shelter shorelines, and clean contaminated water.

This project can be viewed here, or listen to 99% Invisible’s podcast on the project here.

New Brighton Salt Marsh: Connect Landscape Architecture
Vancouver, BC, Canada

An integration of a restored tidal salt marsh with public park and swimming pool in a complex urban/industrial area of Vancouver.

This project can be viewed here.

Lakes are formed by the filling of geological depressions or the containment of water by dams. Characteristics such as the depth, shape, and shoreline of lakes help to determine the hydrology and biology of their respective ecosystems.¹  They are important ecosystems as they provide many services including the provision of drinking water, irrigation supply, flood control, hydropower, transportation, biodiversity conservation, recreation, and aesthetics.² Marshes, however, go through cycles of flooding and drying, and inland marshes specifically can be characterized by their emergent vegetation, grasses, rushes, and sedges.³ Further information about marshes can be found under wetlands.

[1] Suring, “Lentic Freshwater.”

[2] Jørgensen, “Freshwater Lakes.”

[3] Craft, “Inland Marshes.”

Lakes and ponds

Anthropogenic activity around lakes causes various concerns, particularly surrounding water quality. Eutrophication is a primary concern of lake health as wastewater, industrial or agricultural drainage, and/or runoff causes the inflow of excess nutrients into lakes, ultimately damaging the lake’s ecosystem through the impact on oxygen levels and subsequently the aquatic species affected by the chemical change. Runoff and wastewater also have the potential to transfer pathogens into the lakes, thus impacting the safe consumption of lake water. Another impact on lakes is large changes in water levels caused by the diversion of incoming water or by the removal or use of large quantities of water from these waterbodies. Changes in water level have the potential to trigger other processes such as eutrophication or salinization, or impact the ecosystem in other ways, for instance, through the reduction of fish spawning habitat caused by siltation.¹ Additional impacts include fishing, noise and light pollution, and the introduction of invasive species.² Ultimately, it’s important to understand that activities associated with lakes and ponds, and those upland of these waterbodies, will have an impact on the water quality and therefore need to be properly managed to minimize disruptions to these ecosystems.

[1] Jørgensen, “Freshwater Lakes.”

[2] Strecker, McGrew, and Chiapella, “Lake and Pond Ecosystems.”

In lakes and reservoirs where the water has been negatively impacted, restoration processes can be implemented to help bring back the natural potential of the waterbody. The primary methods of lake restoration include the removal of contaminants, the reduction/prevention of agricultural runoff and wastewater from entering to prevent processes such as eutrophication, and the overall improvement of water quality and aquatic ecosystems. Methods of lake restoration should be carried out at a watershed scale as water is interconnected in its different forms throughout the water cycle.¹

[1] Dhir, “Wetland, Watershed, and Lake Restoration.”

Craft, Christopher. “Inland Marshes.” In Creating and Restoring Wetlands, 117–61. Elsevier, 2022. https://doi.org/10.1016/B978-0-12-823981-0.00014-9.

Dhir, Bhupinder. “Wetland, Watershed, and Lake Restoration.” In Handbook of Ecological and Ecosystem Engineering, edited by Majeti Narasimha Vara Prasad, 1st ed., 247–59. Wiley, 2021. https://doi.org/10.1002/9781119678595.ch13.

Jørgensen, Sven E. “Freshwater Lakes.” In Encyclopedia of Ecology, 509–13. Elsevier, 2008. https://doi.org/10.1016/B978-0-444-63768-0.00339-5.

Marsh, G. Alex, and Rhodes W. Fairbridge. “Lentic and Lotic Ecosystems.” In Environmental Geology, 381–88. Encyclopedia of Earth Science. Dordrecht: Kluwer Academic Publishers, 1999. https://doi.org/10.1007/1-4020-4494-1_204.

Strecker, Angela L., Alicia McGrew, and Ariana Chiapella. “Lake and Pond Ecosystems.” In Reference Module in Life Sciences, B9780128225622000700. Elsevier, 2022. https://doi.org/10.1016/B978-0-12-822562-2.00070-0.

Suring, Lowell H. “Lentic Freshwater: Lakes.” In Encyclopedia of the World’s Biomes, 121–30. Elsevier, 2020. https://doi.org/10.1016/B978-0-12-409548-9.12074-3.

“Identified as the first phase of development of Jurong Lake Gardens, Singapore’s third national garden and the first in the heartlands, Lakeside Garden is a 53-hecare site that looks to restore the landscape heritage of the freshwater swamp forest as a canvas for recreation and community activities. The development is envisioned to be a “people’s garden” accessible to all segments of the community and is a conscious effort to bring back the nature that was once unique to the area.”

This project can be accessed on Landezine and the firm’s website.

Rivers then and today have many functions, including the generation of electricity, the supply of water, transportation, the harvesting and cultivation of fish, recreational uses, and the transportation of sediment.^1,2

Streams and rivers are formed as rainfall travels as surface runoff into the channels of streams and rivers or through groundwater stores in which groundwater emerges from springs onto the surface. As water emerges from groundwater springs and merges into other streams, the width of the channel and the water flow generally increases, and as it increases in size, the stream may be identified as a river.³ (As noted by Hildrew and Giller, “There is really no formal definition of this change, and terminology is largely a point of view and culturally determined”).⁴

[1] Dhir, “Wetland, Watershed, and Lake Restoration.”

[2] Marsh and Fairbridge, “Lentic and Lotic Ecosystems.”

[3] Hildrew and Giller, The Biology and Ecology of Streams and Rivers.

[4] Hildrew and Giller.

The various factors affecting the natural functioning of rivers include water pollution, the extraction and increased demand of water, the manipulation of stream channels, the use of water for hydropower, expansion of agriculture, overfishing, introduction of alien species, and artificial light and noise, which disrupt the normal behaviour of aquatic species. Additionally, climate change, especially its associated increased temperatures, is threatening freshwater ecosystems through diminished areas of these waterbodies, altered precipitation patterns, and more frequent flooding and drought events.¹

Water pollution comes from various agricultural and industrial sources, and incorporates many contaminants, which range from pesticides to plastic particles and endocrine disruptors. Additionally, agriculture contributes to increased sedimentation as soil erosion washes sediments into nearby streams.²

In urban regions, the area of impervious surfaces is much greater, leading to decreased infiltration and increased amounts of runoff that makes its way into streams. Urban streams therefore have more frequent flooding events than forested streams. They also typically have higher concentrations of chemicals that are received from wastewater, storms sewers, and runoff. Additionally, since many cities have combined sewer and stormwater pipes, rainstorms will contribute to sewer overflows, resulting in effluents released into urban streams.³

[1] Hildrew and Giller.

[2] Hildrew and Giller.

[3] Meyer, “Urban Aquatic Ecosystems.”

With the factors influencing lotic ecosystems, restoration is an important consideration for streams and rivers. Streams are often impacted by the modification of its channels, and restoration therefore involves the reversal of these changes, such as the widening of the stream’s channels and the regrowth of its riparian vegetation.¹ The restoration of streams and rivers is often much more intricate though, and includes not only structural modifications, but also physical, chemical, and biological methods to alter water flow and restore plants and aquatic species. Restoration of rivers and streams aims to promote channel-floodplain connectivity and restore the natural water and sediment dynamics, which can be done in a multitude of different ways. These methods, however, involve many different stakeholders and a comprehensive understanding of the respective watershed.²

[1] Dhir, “Wetland, Watershed, and Lake Restoration.”

[2] Dhir.

Dhir, Bhupinder. “Wetland, Watershed, and Lake Restoration.” In Handbook of Ecological and Ecosystem Engineering, edited by Majeti Narasimha Vara Prasad, 1st ed., 247–59. Wiley, 2021. https://doi.org/10.1002/9781119678595.ch13.

Hildrew, Alan, and Paul Giller. The Biology and Ecology of Streams and Rivers. 2nd ed. Oxford University PressOxford, 2023. https://doi.org/10.1093/oso/9780198516101.001.0001.

Marsh, G. Alex, and Rhodes W. Fairbridge. “Lentic and Lotic Ecosystems.” In Environmental Geology, 381–88. Encyclopedia of Earth Science. Dordrecht: Kluwer Academic Publishers, 1999. https://doi.org/10.1007/1-4020-4494-1_204. Meyer, J.L. “Urban Aquatic Ecosystems.” In Encyclopedia of Inland Waters, 367–77. Elsevier, 2009. https://doi.org/10.1016/B978-012370626-3.00236-2.

Glaciers have a variety of important functions, including:

The storage and provision of water. Glaciers store water and feed rivers and groundwater that is then used for human and industrial use.

The survival of their respective native vegetation. The melting of glaciers provides water for vegetation near glaciated areas, especially in elevated environments where water is scarce.

Aesthetics and recreation. Glaciers contribute to a variety of outdoor recreational activities such as mountaineering, hiking, or skiing.

They provide a glimpse into history. As glaciers are formed by layers of ice layering year by year, the sampling of ice provides insight into atmosphere conditions of the past¹.

[1] Taillant.

Ice sheets. These are large masses of glacial ice that are also referred to as continental glaciers. There are two major ice sheets that currently exist, one in Greenland and one in Antarctica, each covering tens of thousands of square kilometers of land¹.

Ice shelves. These are floating ice sheets that extend from land masses. They create a barrier around land that slows the migration of ice sheets into the ocean and may contribute to the slowing of sea level rise due to this function².

Icebergs. These are not a type of glacier, but rather pieces of a glacier that are broken off ice shelves in a range of sizes. They provide nutrients as they melt that act to nourish plankton, fish, and other aquatic life³.

Additionally, while not a glacier itself, there is another region with large amounts of stored ice called the periglacial environment. These environments store these quantities of ice below the surface of the earth. During the winter, the periglacial environment freezes, capturing humidity underneath and storing it as ice. It subsequently warms and melts in the summer, releasing water to the lower ecosystem. Some portions called permafrost, however, are continuously frozen, or frozen for a large percentage of the time. A characteristic of the periglacial environment is a lack of vegetation, as plants have difficulty surviving in the thaw-freeze cycles. These environments will survive beyond the melting of glaciers, and therefore may play an important role in water provision⁴.

[1] Knight, Glaciers.

[2] “Glaciers, Ice Sheets, and More: A Primer on the Different Types of Polar Ice.”

[3] “Glaciers, Ice Sheets, and More: A Primer on the Different Types of Polar Ice.”

[4] Taillant, Glaciers: The Politics of Ice.

Due to rising temperatures, spurred by climate change, glaciers are shrinking and being pushed up vertically as they move to cooler environments. As the climate becomes too warm, glaciers will melt altogether, and will no longer serve their important role of storing and releasing water back into the environment¹.

Other anthropogenic activities have an impact on glaciers, with increased industrial activity near glaciers being one of them, as they alter the microclimates around glaciers. The dust and particles from industry can also contaminate glaciers and provoke glacial melt. The activities of industry emit carbon as well, interfering and darkening the surface, triggering temperature changes².

[1] Taillant.

[2] Taillant.

As glaciers melt, chunks of ice may fall into lakes and valleys below. They can also dam lakes, which, when melted, will release large amounts of water rapidly into downstream areas and tributaries¹.

The vanishing of glaciers will cause environments that were once protected by ice to be susceptible to erosion which will impact biodiversity within these regions. There will also be a strain on hydroelectric power supplies, agricultural water supplies, and of course, drinking water. If glaciers melt altogether, snow melt will be the primary provider for rivers, but will ultimately be seasonal as it too will melt in warmer weather, creating prolonged dry periods throughout the year. Rivers will be seasonal and basins that rely on glaciers for their water supply will go dry, prompting water shortages for hundreds of millions of people².

[1] Taillant.

[2] Taillant.

“Glaciers, Ice Sheets, and More: A Primer on the Different Types of Polar Ice.” https://news.climate.columbia.edu/2018/02/05/glaciers-ice-sheets-polar-ice/.

Knight, Peter G. Glaciers. Stanley Thornes, 1999. https://read.kortext.com/reader/pdf/494836/4.

Taillant, Jorge Daniel. Glaciers: The Politics of Ice. Oxford University Press, 2015. https://ebookcentral.proquest.com/lib/ubc/reader.action?docID=2033574.

Glaciers: The Politics of Ice by Jorge Daniel Taillant

This book provides an understanding of glaciers, their role in the environment, and the various types of glaciers and ice. It also introduces the periglacial environment and the importance of this ecosystem. Going beyond this, it addresses how climate change currently is- and will continue to- melt glaciers and what the subsequent impacts of receding glaciers are. There is, however, hope offered through the story of the enactment of a glacial protection law, as well as examples of how individuals are working to preserve or create glaciers, which may be accessed within Chapter 8 “Amazing Glacier Stuff”.

“The natural landscape was the inspiration for the design and also informed the materiality. The thrust-fault geological movement in the area has created a fractal landscape, influencing the architectural form. The angular forms, rusted hues, and warm texture of the Corten steel finish relate to the rocky outcroppings of the surrounding mountains. The glazing mimics the glacial flow below.”

This project can be viewed on the firm’s website and on ArchDaily.

“This thesis explores and demonstrates that landscape architecture, a field that is, until now, uninvolved in retreating glacial landscapes, has the capacity to address the psychological experience of glacier retreat in order to foster engagement with environmental degradation.”

This thesis can be viewed here.

The flow of water through the watershed is dictated by many characteristics, including the shape of the watershed, the topography, the geology, the soil composition, and land use and cover. Due to these variables, the composition of watersheds will vary, but includes streams, tributaries, groundwater, a receiving waterbody or basin outlet, and often sub-basins.¹

Water is inputted into the watershed through precipitation or snowmelt, and then subsequently stored, converted into other forms, or diverted via runoff and streamflow. When water is stored, it occurs through water uptake by plants, through storage at the surface of soil, and via groundwater recharge. Water uptake occurs in varying capacities according to the amount or type of vegetative cover. A portion of the water uptake is later released into the water cycle through evaporation, transpiration, or evapotranspiration.²

[1] Letsinger et al., “Geohydrology.”

[2] Letsinger et al.

The urban environment has a tremendous impact on the functioning of watersheds, with the following stresses being induced:

• The loss of natural habitat, thus threatening biodiversity
• Heat islands
• The alteration of hydrological and biogeochemical cycles
• The introduction of pollutants into ground and surface water¹
• Increased vulnerability in the event of natural disasters such as storms, floods, droughts, and landslides²

[1] Huang et al., “Patterns and Distributions of Urban Expansion in Global Watersheds.”

[2] Huang et al., “Patterns and Distributions of Urban Expansion in Global Watersheds.”

The management of a watershed requires a multi-disciplinary approach, and because of this, it’s important as a designer to be aware of the broader system (watershed) that designs are situated within, as well as the impacts facing each respective watershed as each are unique in their composition. The link HERE provides the delineations of the watersheds within Canada at various scales.

As the impacts on watersheds are often experienced during pronounced climatic events, it is important to consider how designs will respond to such events, as the timing and intensity of these weather patterns themselves cannot be controlled. During periods of precipitation, for example, water can be taken up by plants, recharge groundwater, accumulate in areas where the water table is already high and the soil is saturated, or contribute to runoff.¹ As such, below are a few important considerations:

• The placement of vegetation. Increased infiltration of water (through methods such as planting) helps reduce runoff, mitigate flooding, and increases the groundwater levels to reduce drought during periods of low precipitation. This is critical in areas of steep terrain as fast-moving water and instable slopes create the risk of landslides (insert hyperlink to landslide blog here). It is also critical along riparian buffers that intercept the runoff that will flow into aquatic systems².
• Land use considerations. This includes both the topography (steepness of terrain in particular) and the varying land types that comprise watersheds. Some of the land types included in this assessment are agricultural land, forest land, urban areas, riparian zones, and waterbodies. The various land types are unique in their composition, yet all impact the health of the watershed and should therefore be considered holistically when undergoing watershed management. For example, agricultural lands are often high in water consumption and contribute pollutants into the watershed through their fertilization requirements. Interventions in agricultural lands may include vegetated filter strips to slow runoff and the movement of pollutants, as well as cover crops to improve soil health. They should be appropriately placed in consideration of the adjacent land type within the watershed³.
• Impermeable surfaces and the use of blue-green infrastructure. Urban development increases the amount and area of impermeable surfaces. This then diverts and increases runoff as water is unable to permeate through soil. Soil compaction is also increased, which similarly reduces infiltration and thus increases runoff. To mitigate these effects, designs can incorporate architectural solutions such as permeable surfaces and blue-green infrastructure⁴.

[1] Tomer, “Watershed Management.”

[2] Letsinger et al., “Geohydrology.”

[3] Tomer, “Watershed Management.”

[4] Tomer.

Huang, Qingxu, Han Zhang, Jasper Van Vliet, Qiang Ren, Raymond Yu Wang, Shiqiang Du, Zhifeng Liu, and Chunyang He. “Patterns and Distributions of Urban Expansion in Global Watersheds.” Earth’s Future 9, no. 8 (August 2021): e2021EF002062. https://doi.org/10.1029/2021EF002062.

Letsinger, Sally L., Allison Balberg, Elias Hanna, and Erin K. Hiatt. “Geohydrology: Watershed Hydrology.” In Encyclopedia of Geology, 442–56. Elsevier, 2021. https://doi.org/10.1016/B978-0-12-409548-9.12389-9.

Tomer, M.D. “Watershed Management.” In Reference Module in Earth Systems and Environmental Sciences, B978012409548909117X. Elsevier, 2014. https://doi.org/10.1016/B978-0-12-409548-9.09117-X.

Watershed Characterization: City of Vancouver

This document that provides an overview of the City of Vancouver’s urban watersheds as well as insight into the various factors affecting their health and management.

Watershed Management by M.D. Tomer

This article provides an overview of the factors affecting watershed health, with an emphasis on how the role of water quality and land use contribute to and are affected by climatic events. In summarizing the complexity of issues facing watersheds, as well as the importance of considering local conditions, it provides an insight into watershed assessment and a brief methodology for how watershed management may be approached.

“EPA addresses water pollution from the watershed approach, a comprehensive framework for addressing water resource challenges….Restoring water quality is most effective when pollution sources, stressors and solutions are identified for the entire watershed.”