Category: Water and Climate

The sea levels of the world’s oceans are currently on the rise due to the following contributing factors:

• Rising temperatures caused by carbon emissions leading to ocean thermal expansion
• The melting of glaciers and ice caps
• The melting of the ice sheets of Greenland and Antarctica

The impacts of sea level rise are not evenly spread and will vary across regions, particularly due to subsidence from human activity which will result in a higher sea level within these areas, thus increasing their vulnerability.¹

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[1] “Sea-Level Rise from the Late 19th to the Early 21st Century | Surveys in Geophysics.”

In coastal regions, the impacts of sea level rise include erosion, flooding, salinization, loss of habitat, and a decrease in habitat function and biodiversity. The carbon emissions causing ocean warming are also increasing acidification and oxygen loss, thereby impacting aquatic ecosystems. This has contributed to large-scale coral bleaching and reef degradation as well as a reduction in the biodiversity of intertidal zones, specifically rocky reefs, in which species are particularly sensitive to rising temperatures and acidification. In estuaries specifically, the increase in nutrients and organic matter have increased eutrophication and have led to the enlargement of hypoxic areas.¹

Along with the impacts to landscapes, the impacts extend to urban areas as the changes in temperature, oxygen levels and acidity have produced algal blooms and the occurrence of pathogens which impact food provisioning and human health. With sea level rise, there is also a global impact on food security, especially in low latitude, developing coastal communities who rely on seafood for nutrient requirements (Central and West Africa). Furthermore, there are cultural implications for many communities who have strong connections with the natural habitat of their regions and who come to rely on the harvesting of marine life for cultural and spiritual purposes, in addition to sustenance. Indigenous communities are particularly vulnerable as the reliance on the ocean for their livelihoods and culture is shifting and affecting their ability to pass on traditional knowledge or use their traditional harvesting techniques. Additionally, economies are affected through the impact on fisheries, marine tourism, and coastal buildings and infrastructure.²

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[1] “Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities — Special Report on the Ocean and Cryosphere in a Changing Climate.”

[2] “Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities — Special Report on the Ocean and Cryosphere in a Changing Climate.”

Designers may respond to rising sea levels through a few different strategies.

The first of which is to create hard protection against water inundation through flood barriers such as levees, dikes, seawalls, breakwaters, and jetties. These are often found in urban coastal areas but have drawbacks that include the destruction of intertidal habitat through processes such as coastal squeeze and technical limits that constrain their effectiveness.

Designers may also modify buildings themselves through the elevation of structures and important utilities and through waterproofing.

A third strategy is through ecosystem-based adaptations, including both coral and wetland conservation. While wetland conservation and restoration preserve these essential intertidal habitats, these processes require a large portion of land, and are therefore not always feasible.

Lastly, designers can use coastal retreat through planned relocation of buildings or communities in areas where sea level rise is an immediate threat.¹

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[1] “Technical Summary — Special Report on the Ocean and Cryosphere in a Changing Climate.”

“Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities — Special Report on the Ocean and Cryosphere in a Changing Climate.” https://www.ipcc.ch/srocc/chapter/chapter-5/.

“Sea-Level Rise from the Late 19th to the Early 21st Century | Surveys in Geophysics.” https://link.springer.com/article/10.1007/s10712-011-9119-1.

“Technical Summary — Special Report on the Ocean and Cryosphere in a Changing Climate.” https://www.ipcc.ch/srocc/chapter/technical-summary/.

“The South Bay Sponge is an innovative model for how to adapt our urban coastal areas in the face of climate change, as many cities around the world face unprecedented threats from rising sea levels with increased flooding and related storm damage to infrastructure and settlement.”

This project can be viewed on the Field Operations website and through Rebuild By Design.

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As an alternative to dikes HafenCity has fallen back on the settlement pattern traditional in the North Sea area, the “Warft”…The “Warft” model protects HafenCity’s residents, workers and visitors even in the case of severe flooding. Even during the strong storm surges that occur about twice a year today, city life on the “Warft” can continue largely unaffected. The promenades are only flooded for a brief period.”

This project can be viewed on the city’s website and here.

Droughts are a result of a decrease in normal levels of precipitation over varying time and spatial scales, resulting in a water shortage that is relative to the normal levels in the identified extent. The time scale may range from short-term events that last mere weeks to droughts that last for years or decades. The spatial scale is equally wide-ranging as droughts can be community-specific and small in scale or they can span across continents¹. The decrease in precipitation that elicits droughts can be compounded by the impacts from water usage, distribution, planning, and management, thus increasing their severity². The susceptibility to drought is increasing due to a varying climate and a growing human population, which puts demands on water for consumption, industrial usage, and agriculture, amongst other various uses³.

Within a broader definition of drought are the following further classifications: meteorological droughts, agricultural droughts, hydrological droughts, and socioeconomic droughts.

Meteorological droughts derive from a stretch of unusually dry weather, resulting in a hydrologic imbalance. They are measured or characterized by the intensity and duration of dryness^4,5.

Agricultural droughts occur when a shortage of precipitation negatively impacts the crop production. Agriculture is the first system to be impacted due to a decrease in soil moisture and is thus measured and influenced by a deficit in precipitation, evapotranspiration, and soil moisture⁶.

When there are prolonged periods of a precipitation shortage, a hydrological drought may occur. These droughts are associated with a shortage of water in streams, lakes, reservoirs, and groundwater. As the water in reservoirs and rivers are used for many different purposes such as irrigation and power generation, it may be difficult to quantify the impacts of drought⁷.  

Socioeconomic droughts occur when the water supply reaches a critical level that impacts human activities and ecosystem function. These droughts are concerned with the impact on supply and demand that is associated with the three previous drought categories⁸.

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[1] Cook, Drought.

[2] Quiring, “HYDROLOGY, FLOODS AND DROUGHTS | Drought.”

[3] “Definition of Drought | 1 | Handbook of Drought and Water Scarcity | N.”

[4] Quiring, “HYDROLOGY, FLOODS AND DROUGHTS | Drought.”

[5] “Definition of Drought | 1 | Handbook of Drought and Water Scarcity | N.”

[6] Quiring, “HYDROLOGY, FLOODS AND DROUGHTS | Drought.”

[7] Quiring.

[8] “Definition of Drought | 1 | Handbook of Drought and Water Scarcity | N.”

The impacts of droughts are far-reaching, including a reduction in agricultural production, the formation of wildfires, the destruction of plants and habitats, water shortages, the restriction of waterways for navigation and recreation, and a loss of ecosystem services¹. Extensive droughts can lead to desertification². Other impacts include economic costs, as declines in hydropower production requires the generation of power from other sources, thus increasing the associated costs³. With these impacts, also comes larger political issues such as conflict amongst regions for water usage, social unrest, civil strife, and climate refugees⁴.

Health impacts

Droughts have a significant impact on human health overall, stemming from a shortage of drinking water, decline in water quality, effects on air quality and sanitation and hygiene, shortage of food, the increase in virus transmission, as seen in California with the West Nile virus, and even fatalities⁵.

Water quality. Water shortages may prompt a reduction in stream flow, thus increasing the concentration of pollutants, chemical, or human pathogens in aquatic organisms, or leading to higher temperatures and reduced oxygen levels⁶. An increase in precipitation following this may cause the release of this water, resulting in chemical pollution⁷.

Air quality. With an increase in the consequences of droughts, such as wildfires, comes an increase in the particulates within air, irritating the lungs and contributing to respiratory infections. As water levels change, an increase in freshwater blooms may also occur, also negatively impacting air quality⁸.

Disease Transmission. As the behaviours of insects and animals change, they may come into closer contact with humans, putting people at risk of contracting the diseases they carry⁹.

Malnutrition. This stems from a drop in agricultural productivity, leading to increased price of foods and reduced food security¹⁰.

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[1] Cook, Drought.

[2] Panikkar, “Drought Management in an Urban Context.”

[3] Cook, Drought.

[4] Quiring, “HYDROLOGY, FLOODS AND DROUGHTS | Drought.”

[5] “Health Implications of Drought | CDC.”

[6] “Health Implications of Drought | CDC.”

[7] Panikkar, “Drought Management in an Urban Context.”

[8] “Health Implications of Drought | CDC.”

[9] “Health Implications of Drought | CDC.”

[10] IPCC, “Climate Change 2023 Synthesis Report.”

There are a few ways that designers can intervene to help conserve and reuse water and improve the quality of water as well.

Restoration of wetlands, peatlands, and upstream forest ecosystems. These ecosystems enhance natural water retention and improve water quality¹.

Reduction of impermeable surfaces. As impermeable surfaces do not allow for the infiltration of rainwater, it is best to reduce the area of impermeable surfaces and increase the total planted area as this supports groundwater recharge².

Native planting. Since native plants are better adapted to local conditions, they often require less watering and require less maintenance or chemical intervention (fertilizers and pesticides)³.

Rainwater harvesting. This allows water within a building, landscape, or region to be reused to conserve potable water, and provide water in times of drought. Within a building, blue-green roofs provide water storage below the soil layer to then evaporate or to be used for the water requirements within the building or surrounding landscape⁴.

Agroforestry. This is a practice in which trees are grown on the same plot as ground crops as a means of increasing soil moisture and rainwater infiltration and reducing the demand on irrigation^5,6.

Irrigation. While methods such as basin irrigation may reduce drought risk, it must be effectively managed as it has the potential to accelerate the depletion of groundwater^7,8.

Living roofs (Green roofs). Green roofs act to reduce stormwater runoff, storing precipitation for subsequent evapotranspiration, and ultimately acting as retention and detention areas. Green roofs are one method of introducing LID (Low Impact Development) into the urban environment⁹. A more detailed explanation of the role of green roofs can be found here.

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[1] IPCC.

[2] Watson and Adams, Design for Flooding : Architecture, Landscape, and Urban Design for Resilience to Climate Change.

[3] Watson and Adams.

[4] Watson and Adams.

[5] IPCC, “Climate Change 2023 Synthesis Report.”

[6] “5 Ways to Deal with Drought in Africa and Beyond.”

[7] IPCC, “Climate Change 2023 Synthesis Report.”

[8] “Definition of Drought | 1 | Handbook of Drought and Water Scarcity | N.”

[9] Roehr and Fassman-Beck, Living Roofs in Integrated Urban Water Systems.

“5 Ways to Deal with Drought in Africa and Beyond.” https://www.afd.fr/en/actualites/5-ways-deal-drought-africa-and-beyond.

“2022 Global Natural Disaster Assessment Report | PreventionWeb.” https://www.preventionweb.net/publication/2022-global-natural-disaster-assessment-report.

Cook, Ben. Drought. Columbia University Press, 2019. https://www.degruyter.com/document/doi/10.7312/cook17688/html?_llca=transfer%3A77f9860664252c29c25049871821c66a&_llch=9c98ee42f177768cbd03920610962bba76f4ac27273585ec85754bdcd4e62550.

“Definition of Drought | 1 | Handbook of Drought and Water Scarcity | N.” https://www.taylorfrancis.com/chapters/edit/10.1201/9781315404219-1/definition-drought-neil-coles-saeid-eslamian?context=ubx&refId=23a84fd7-6dcb-47ff-acfa-daf0da1da4c2.

“Drought.” https://www.who.int/health-topics/drought.

“Health Implications of Drought | CDC.” https://www.cdc.gov/nceh/drought/implications.htm.

IPCC. “Climate Change 2023 Synthesis Report,” 2023. https://www.ipcc.ch/report/ar6/syr/.

Panikkar, Avanish K. “Drought Management in an Urban Context.” Griffith University, n.d.

Quiring, S. “HYDROLOGY, FLOODS AND DROUGHTS | Drought.” In Encyclopedia of Atmospheric Sciences, 193–200. Elsevier, 2015. https://doi.org/10.1016/B978-0-12-382225-3.00037-2.

Roehr, Daniel, and Elizabeth Fassman-Beck. Living Roofs in Integrated Urban Water Systems. London, UNITED KINGDOM: Taylor & Francis Group, 2015. http://ebookcentral.proquest.com/lib/ubc/detail.action?docID=1983421.

Watson, Donald, and Michele Adams. Design for Flooding : Architecture, Landscape, and Urban Design for Resilience to Climate Change. John Wiley & Sons, 2010. https://ebookcentral.proquest.com/lib/ubc/reader.action?docID=624403&ppg=20#.

“By removing trees and restoring the original prairie, savannah, and woodland ecosystems found at the Arboretum, the landscape architects designed a landscape naturally resilient to future climate shocks, such as more frequent and severe hurricanes, flooding, and drought.”

This project can be viewed on ASLA and the Arboretum website.

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“The approach aims to integrate green infrastructure solutions that reduce water consumption and encourages re-use at a local scale, while counteracting climate change impacts such as drought and urban heating, and minimizing polluted overflows into the region’s waterbodies.”

This project is introduced here and the Cambie Corridor Plan can be accessed here.

Flooding occurs when water inundates an area of land that is typically dry. Floods can occur by various means: they may be the direct result of heavy precipitation, they may occur by the failing of infrastructure such as dams and levees, they can arise by the melting of snowfall or the breakup of ice dams on a river, they can be the result of the aftermath of earthquakes, or they may be caused by other atmospheric events such as tsunamis or storm surges that inundate coastal areas¹.

Additionally, with the increase in wildfire occurrences comes a risk of erosion and flooding, which are common after extreme fires. Flooding occurs after wildfires due to the alterations in soil conditions, which include the formation of a water-repellant layer and higher erodibility. It is most likely to happen during summer or fall storms during the year of a fire or following a drought in subsequent years. This is due to dry soils, as they have the greatest water repellency, and a loss of forest and vegetative cover following the fire².

While the most common causes of flooding are due to meteorological factors such as heavy precipitation and snowmelt, human activities also have a significant impact on the production and intensity of floods³.

Human activities:

Urbanization affects all aspects of the hydrological cycle. It contributes to compacted and impermeable surfaces, producing low infiltration rates, thus increasing runoff. When this occurs in cities, the stormwater sewers can exceed their capacity, resulting in flooding which is particularly problematic in combined stormwater-sewage systems. Urbanization and agricultural development also often involve the removal of natural vegetation which reduces the water absorption of the soil, inevitably increasing both the quantity and velocity of runoff. This can also contribute to soil erosion due to the loss of roots that anchor the soil in place. Additionally, the draining of wetlands for urban developments has aggravated the effects of floods due to their inherent flood-reducing characteristics⁴.

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[1] Doswell, “HYDROLOGY, FLOODS AND DROUGHTS | Flooding.”

[2] Curran et al., “Large-Scale Erosion and Flooding after Wildfires.”

[3] Jones, “Human Modification of Flood-Producing Processes.”

[4] Jones.

Flash floods are produced when heavy rainfall causes a rise in water in a short time period, typically occurring within small catchment areas. Areas of steep and rocky terrain, and densely populated areas, are particularly susceptible to flash floods as there are high levels of water runoff and limited absorption to counteract this. They are especially dangerous as these events happen very rapidly, leaving little time to prepare for evacuation, despite the forecasting of precipitation¹.

River floods occur much more gradually, as individual rainfall events may accumulate, sending runoff into the main river from its surroundings or from a network of tributaries. The water level within the river will gradually rise, which may be compounded by other factors such as snowmelt, leading to flooding. Due to the longer timescale, there is more time to respond to the threat of rising water levels, thus reducing human injuries and fatalities. There are, however, associated factors with river floods, which include dam or levee failures, that can lead to conditions similar to those of a flash flood. Additionally, water may be intentionally released from dams or levees to prevent complete failure of these systems².

Coastal areas are facing an increase in the frequency and intensity of storms, which are compounded by a rising sea level, resulting in coastal flooding. Storm surges from extreme storms have contributed to a great number of fatalities. Other impacts are beach erosion, disruption to ecosystems, salinization, and, similar to the other floods, damage to infrastructure³.

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[1] Doswell, “HYDROLOGY, FLOODS AND DROUGHTS | Flooding.”

[2] Doswell.

[3] Warrick et al., “Climate Change, Severe Storms, and Sea Level.”

Human health impacts (it is important to note that the human impact is much greater in developing countries):

• Fatalities- which is greatly related to the velocity of floodwaters, may occur due to drowning or being struck by debris carried by waters
• Infectious disease transmission,
• Mental health impacts¹,
• Compromised drinking water because of water containing chemicals, microorganisms, and suspended silt

Damage to infrastructure and natural vegetation due to the energy of the moving water and the debris the water carries, which may include anything it sweeps away in its path or due to water immersion. Along floodplains, entire crops may be lost when inundated with water. Evidently, the resulting economic impact of this can be enormous.

Dirt and debris are left behind, which present health threats as well as high costs for cleanup and removal

They can relocate wild animals from their natural habitats to areas of proximity to humans.²

Positive results of floods:

• As flooding is a natural process, floodplains are highly fertile regions, rich in nutrients due to the deposition of nutrients by floods³.
• Rainwater restores and stabilizes the vegetative soil layer and purifies regions that may be prone to salinity.⁴

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[1] Few et al., “Floods, Health and Climate Change: A Strategic Review.”

[2] Doswell, “HYDROLOGY, FLOODS AND DROUGHTS | Flooding.”

[3] Doswell.

[4] Watson and Adams, Design for Flooding : Architecture, Landscape, and Urban Design for Resilience to Climate Change.

Considerations of design that mitigates flooding ranges in scale from the building to the regional landscape and beyond with flood mitigation and floodplain management strategies. In “Design for Flooding : Architecture, Landscape, and Urban Design for Resilience to Climate Change”, a range of approaches to flood mitigation are presented. A few of these will be outlined below.

Small Scale

Impervious surfaces. As a general practice, it is best to reduce the area of impervious surfaces. During mild rainfall events, the runoff that occurs will be transferred by impervious surfaces, and because of this, the impervious surfaces should direct water towards vegetated areas. In these events, it is best for the rainfall to be managed in its immediate vicinity. Roof downspouts can direct water to vegetated areas provided the grading of the landscape is sloped to keep water away from the structure. It is important to note that lawns can be almost as impervious as hardscape, and they too should be sloped to direct water towards natural planted areas¹.

Bioretention areas (Rain gardens). These are designed to absorb runoff from surrounding hardscapes, and thus should be located adjacent to impervious surfaces and lawns. Not only do they absorb runoff, but the plants act to filter the water and remove pollutants. They are best suited for milder rainfall events as heavy rainfall events would require an overflow, perhaps to a bioswale which stores water during lower precipitation and moves it at a slower velocity in periods of heavy inundation².

Medium Scale

Rainwater harvesting. This process reuses water that falls on site through the storage during heavy rainfall and distribution when groundwater needs recharging³.

Native planting. As native plants are attuned to local conditions, they often require less watering and do not constitute the need for fertilizer use or frequent maintenance. In getting rid of landscapes that require fertilizers or other chemicals, the pollutants that are carried away due to flooding are reduced⁴.

Shoreline protection. Structural protection measures should be used minimally, and instead, when possible, be substituted for the restoration and revegetation of natural shorelines, the restoration of wetlands, adapting to sea level rise through setbacks, and reducing shoreline erosion through vegetative and geotextile means⁵.

Large scale

Riparian buffers. See page on riparian zones here.

Wetland restoration. See page on wetlands here.

Ecological wastewater treatment systems. This is a process of remediating wastewater through biological processes before it is reused or enters back into waterbodies. This may include a range of systems ranging from biofiltration tanks to wetland construction. This reduces the wastewater discharge into water bodies and streams, as would occur in combined sewer systems⁶.

Phytotechnology planting techniques. Plants may be used to clean up on-site pollutants or where future pollutants are expected to limit the harm of the pollutants on people and the environment.

Construction within floodplains. Due to the inherent flooding that occurs in these areas, construction should be limited or prohibited to protect both people and infrastructure⁷.

Relocation or elevation of infrastructure. When flooding is inevitable, infrastructure can be moved through managed retreat, or alternatively, elevated to prevent damage from water infiltration.

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[1] Watson and Adams.

[2] Watson and Adams.

[3] Watson and Adams.

[4] Watson and Adams.

[5] Watson and Adams.

[6] Watson and Adams.

[7] Watson and Adams.

Design for Flooding : Architecture, Landscape, and Urban Design for Resilience to Climate Change by Donald Watson and Michele Adams

For further information on designing for flood mitigation or adaptation, this resource provides strategies for design, focused on flooding as an opportunity for design rather than solely viewing it as a risk or threat. It overviews the basic principles behind flooding and the meteorological contributions and discusses both local and regional implications of flooding and design, while promoting design through a watershed approach. A comprehensive list of architectural and landscape interventions are provided within this framework. Lastly, the book also provides an overview of national strategies for flood management and briefly introduces the successes of various countries in their approaches.

“2022 Global Natural Disaster Assessment Report | PreventionWeb.” https://www.preventionweb.net/publication/2022-global-natural-disaster-assessment-report.

Curran, Mike, Bill Chapman, Graeme Hope, and Dave Scott. “Large-Scale Erosion and Flooding after Wildfires.” B.C. Ministry of Forests and Range, 2006.

Doswell, C.A. “HYDROLOGY, FLOODS AND DROUGHTS | Flooding.” In Encyclopedia of Atmospheric Sciences, 201–8. Elsevier, 2015. https://doi.org/10.1016/B978-0-12-382225-3.00151-1.

Few, Roger, Michael Ahern, Franziska Matthies, and Sari Kovats. “Floods, Health and Climate Change: A Strategic Review.” Tyndall Centre for Climate Change Research, November 2004.

Jones, J.A.A. “Human Modification of Flood-Producing Processes.” In Floods, by D.J. Parker. Routledge, 2000.

Warrick, R.A., K.L. McInnes, A.B. Pittock, and P.S. Kench. “Climate Change, Severe Storms, and Sea Level.” In Floods, by D.J. Parker, n.d.

Watson, Donald, and Michele Adams. Design for Flooding : Architecture, Landscape, and Urban Design for Resilience to Climate Change. John Wiley & Sons, 2010. https://ebookcentral.proquest.com/lib/ubc/reader.action?docID=624403&ppg=20#.

“Taopu Central Park is the unifying element and urban green lung for Taopu Smart City, a science and technology hub in northwest Shanghai. Inspired by traditional Chinese culture’s tenets of graceful movement and beauty, the park’s dynamic and fluid network of pathways, waterways, and topography improve water quality, manage stormwater, provide an elegant soil remediation strategy, and create connections that transform industrial lands into a living ecosystem and a new kind of urban ecological park for China.”

This project can be viewed here.

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“The Dorchester shoreline stretches 9.5 miles along Boston Harbor and the Neponset River. Open space, marshland, and parks line the waterfront, but these spaces are not connected to each other or to adjacent inland communities. Today, only limited points of access remain, and these align with major inundation pathways. Climate Ready Dorchester expands the vision for the future of the Dorchester shoreline, offering strategies to adapt to coastal flood risk while also establishing a framework to connect the waterfront parks, beaches, and marshes in Dorchester, transforming them into one accessible, continuous waterfront – The Dorchester Shoreway.“

This project can be viewed on SCAPE’s website and on the City of Boston’s website.