{"content":[{"content":{"params":{"text":"

Unit 2: Water management for rooftop and vertical systems<\/h2>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"Unit 2: Water management for rooftop and vertical systems"},"subContentId":"625cd8f6-0229-4357-84b2-1ca11c47facf"},"useSeparator":"auto"},{"content":{"params":{"text":"
Content focus:<\/strong><\/p>\n\n
\n\t
Rainwater harvesting and localised irrigation solutions<\/li>\n\t
Water storage and pressure limitations on buildings<\/li>\n\t
Passive and active reuse (e.g., hydroponic recirculation, condensate collection)<\/li>\n\t
Drainage, runoff, and waterproofing considerations
\n\t <\/li>\n<\/ul>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"Unit 2: Water management for rooftop and vertical systems"},"subContentId":"11e4e8bf-4006-4e9f-9488-5e0c96cf1f0a"},"useSeparator":"auto"},{"content":{"params":{"text":"
1. Water needs and constraints on building surfaces <\/strong><\/span><\/h3>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"1. Water needs and constraints on building surfaces"},"subContentId":"546e12e7-0fbb-4198-9f55-7ce6e72b175c"},"useSeparator":"auto"},{"content":{"params":{"decorative":false,"contentName":"Image","expandImage":"Expand Image","minimizeImage":"Minimize Image","file":{"path":"images\/image-9ndt4KY4.png","mime":"image\/png","copyright":{"license":"U"},"width":903,"height":587},"alt":"1. Water needs and constraints on building surfaces"},"library":"H5P.Image 1.1","metadata":{"contentType":"Image","license":"U","title":"1. Water needs and constraints on building surfaces"},"subContentId":"b45f3d07-e542-445f-a847-428c7a8eb9b8"},"useSeparator":"auto"},{"content":{"params":{"text":"
Water is one of the most critical inputs in any agricultural system, but its management on building surfaces presents a distinctive set of constraints. Rooftops, fa\u00e7ades, terraces, and other structural environments lack the natural water retention characteristics of soil-based systems and are often disconnected from reliable irrigation infrastructure. In such contexts, the efficiency, accessibility, and safety of water use become decisive for the success of the system.<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"1. Water needs and constraints on building surfaces"},"subContentId":"a479b9e7-7844-4af6-b9dd-8f8096cc169e"},"useSeparator":"auto"},{"content":{"params":{"text":"
Factors that influence water needs<\/strong><\/h3>\n\n
Water requirements vary depending on several interrelated factors:<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"Factors that influence water needs"},"subContentId":"320b98d9-1b6c-4dd0-b38d-60e355364fc2"},"useSeparator":"auto"},{"content":{"params":{"mode":"normal","dialogs":[{"text":"
Crop type<\/p>\n","answer":"
Leafy greens like lettuce or spinach require consistent moisture, while Mediterranean herbs such as thyme or oregano are more drought-tolerant.<\/p>\n","tips":{},"image":{"path":"images\/image-91w0nRRD.png","mime":"image\/png","copyright":{"license":"U"},"width":806,"height":589}},{"text":"
System type<\/p>\n","answer":"
Hydroponic and aeroponic systems require continuous or highly regulated water circulation, whereas soil-based planters may tolerate more fluctuation.<\/p>\n","tips":{},"image":{"path":"images\/image-VfJ8fR5a.png","mime":"image\/png","copyright":{"license":"U"},"width":901,"height":603}},{"text":"
Exposure and microclimate<\/p>\n","answer":"
Rooftops and fa\u00e7ades often face higher evapotranspiration rates due to heat, wind, and solar exposure. The urban heat island effect can increase water demand significantly (EEA, 2023) [9].<\/p>\n","tips":{},"image":{"path":"images\/image-U0eYtnGb.png","mime":"image\/png","copyright":{"license":"U"},"width":899,"height":588}},{"text":"
Substrate properties<\/p>\n","answer":"
Lightweight substrates used on rooftops (e.g. coconut coir, perlite, or expanded clay) retain water differently than traditional soil, often requiring more frequent but lower-volume irrigation.<\/p>\n","tips":{},"image":{"path":"images\/image-aGfJ2RwY.png","mime":"image\/png","copyright":{"license":"U"},"width":790,"height":590}}],"behaviour":{"enableRetry":false,"disableBackwardsNavigation":false,"scaleTextNotCard":false,"randomCards":false,"maxProficiency":5,"quickProgression":false},"answer":"Turn","next":"Next","prev":"Previous","retry":"Retry","correctAnswer":"I got it right!","incorrectAnswer":"I got it wrong","round":"Round @round","cardsLeft":"Cards left: @number","nextRound":"Proceed to round @round","startOver":"Start over","showSummary":"Next","summary":"Summary","summaryCardsRight":"Cards you got right:","summaryCardsWrong":"Cards you got wrong:","summaryCardsNotShown":"Cards in pool not shown:","summaryOverallScore":"Overall Score","summaryCardsCompleted":"Cards you have completed learning:","summaryCompletedRounds":"Completed rounds:","summaryAllDone":"Well done! You have mastered all @cards cards by getting them correct @max times!","progressText":"Card @card of @total","cardFrontLabel":"Card front","cardBackLabel":"Card back","tipButtonLabel":"Show tip","audioNotSupported":"Your browser does not support this audio","confirmStartingOver":{"header":"Start over?","body":"All progress will be lost. Are you sure you want to start over?","cancelLabel":"Cancel","confirmLabel":"Start over"},"title":"","description":""},"library":"H5P.Dialogcards 1.9","metadata":{"contentType":"Dialog Cards","license":"U","title":"Factors that influence water needs"},"subContentId":"47366edc-7e6e-4ff6-bd55-600ad01067f4"},"useSeparator":"auto"},{"content":{"params":{"text":"
These constraints demand precise irrigation planning and may require real-time monitoring of water availability and substrate moisture.<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"These constraints demand precise irrigation planning and may require real-time monitoring of water availability and substrate moisture."},"subContentId":"f6e8ba04-d345-4ab2-bfca-e1ac16ac6fb3"},"useSeparator":"auto"},{"content":{"params":{"text":"
Lack of soil absorption and natural infiltration<\/h3>\n\n
Unlike ground-based systems, water on rooftops and fa\u00e7ades cannot infiltrate into the soil. This means that all excess water must be drained, stored, or reused. Poorly managed irrigation can lead to:<\/p>\n\n
\n\t
Waterlogging of containers and root rot<\/li>\n\t
Runoff that damages waterproof membranes or enters building interiors<\/li>\n\t
Unwanted dripping on pedestrians, windows, or machinery<\/li>\n\t
Wasted resources and regulatory violations<\/li>\n<\/ul>\n\n
This makes water use on surfaces a critical balancing act between plant health and technical feasibility. Systems must be designed to deliver the right volume of water at the right time while allowing safe and efficient drainage.
\n
\nAs noted in the FAO\u2019s 2019 report on low-tech urban agriculture [10], rooftop water use is best managed when integrated into closed-loop or recirculating systems, particularly in dense urban settings where water conservation is also a civic concern.<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"Lack of soil absorption and natural infiltration"},"subContentId":"8b67fbd8-7716-4ba4-88ac-ecaa87125f5d"},"useSeparator":"auto"},{"content":{"params":{"text":"
2. Water sourcing: rainwater, greywater, and supply integration <\/strong><\/span><\/h3>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"2. Water sourcing: rainwater, greywater, and supply integration"},"subContentId":"160dbb51-61bc-478e-9653-617a72db9d2f"},"useSeparator":"auto"},{"content":{"params":{"text":"
One of the key challenges in rooftop and fa\u00e7ade-based agriculture is securing a reliable, safe, and sustainable source of irrigation water. In traditional farming, water is often accessed from groundwater, surface flows, or piped irrigation networks. In contrast, building-integrated systems may lack direct access to external infrastructure and must rely on on-site sourcing or alternative delivery models.<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"2. \u00a0Water sourcing: rainwater, greywater, and supply integration"},"subContentId":"4529dd73-dad4-4f39-b446-4f4733cdd876"},"useSeparator":"auto"},{"content":{"params":{"iconType":"icon","icon":"check","color":"#0eb50e","hotspots":[{"position":{"x":35.21634615384615,"y":27.70671996569848},"alwaysFullscreen":false,"content":[{"params":{"text":"
Rainwater collection is a widely promoted strategy in urban agriculture because it utilises free, relatively clean, and decentralised water. Flat rooftops are especially well suited for harvesting, as they can be fitted with simple gutters, filters, and storage tanks. The volume that can be collected depends on:<\/p>\n\n
\n\t
Surface area of the roof<\/li>\n\t
Rainfall frequency and intensity<\/li>\n\t
Storage capacity<\/li>\n<\/ul>\n\n
Rainwater is typically low in dissolved salts and chemicals, making it suitable for hydroponic, container-based, and soil-less systems. However, it must be filtered or treated to remove airborne particulates, bird droppings, or roofing contaminants. First-flush diverters and sediment filters are commonly used to ensure safety.
\nIn its strategic guidance on resource loops, the Ellen MacArthur Foundation (2022) [11] encourages rooftop agriculture to combine food and water systems through rainwater reuse, noting that such combinations \u201cincrease resilience and reduce infrastructure dependence\u201d for urban buildings.
\n <\/p>\n"},"library":"H5P.Text 1.1","metadata":{"contentType":"Text","license":"U","title":"Rainwater harvesting"},"subContentId":"7106ea2b-d516-42e8-8198-9ac718c27843"}],"header":"Rainwater harvesting"},{"position":{"x":35.21634615384615,"y":62.29565559783371},"alwaysFullscreen":false,"content":[{"params":{"text":"
Greywater (wastewater from sinks, showers, or laundry (excluding toilets)) can also be reused for irrigation, provided it is filtered and non-toxic. In industrial or commercial buildings, this water is often available in large quantities, especially where kitchens or sanitary facilities are located nearby.
\nThe feasibility of greywater use depends on:<\/p>\n\n
\n\t
Building regulations and safety standards<\/li>\n\t
Treatment level (filtration, UV sterilisation, or biological systems)<\/li>\n\t
Crop type and irrigation method (e.g., drip irrigation below foliage is preferred to reduce contact with edible parts)<\/li>\n<\/ul>\n\n
Some systems use constructed wetlands or reed beds on rooftops to treat greywater before routing it to planters. These solutions are being piloted in cities like Amsterdam and Berlin as part of wider Nature-Based Solutions (NBS) for urban resilience.
\n <\/p>\n"},"library":"H5P.Text 1.1","metadata":{"contentType":"Text","license":"U","title":"Greywater and building integration"},"subContentId":"ce3bd941-50b7-4c96-b787-505537a84d79"}],"header":"Greywater and building integration"},{"position":{"x":35.21634615384615,"y":97.088030574181},"alwaysFullscreen":false,"content":[{"params":{"text":"
Where local sourcing is not feasible, rooftop farms may rely on mains water supply, often through hoses connected from service areas or rooftop taps. While reliable, this method can increase operational costs and places pressure on city water systems, particularly during drought periods. Automated timers and precision irrigation methods (discussed in 2.3) help minimise consumption.
\n
\nIn some advanced projects, farms are integrated into smart building systems, allowing water use to be tracked alongside energy and waste data for circularity monitoring.<\/p>\n"},"library":"H5P.Text 1.1","metadata":{"contentType":"Text","license":"U","title":"Municipal and on-demand supply"},"subContentId":"7dec5a02-4615-4979-ae59-3a03c8296185"}],"header":"Municipal and on-demand supply"}],"hotspotNumberLabel":"Hotspot #num","closeButtonLabel":"Close","disableScaling":false,"image":{"path":"images\/image-KMIsYLiE.png","mime":"image\/png","copyright":{"license":"U"},"width":1024,"height":599}},"library":"H5P.ImageHotspots 1.10","metadata":{"contentType":"Image Hotspots","license":"U","title":"2. \u00a0Water sourcing: rainwater, greywater, and supply integration"},"subContentId":"7db02c30-5ed7-481e-aed2-bd6c9988a355"},"useSeparator":"auto"},{"content":{"params":{"text":"
3. Irrigation technologies for rooftop and fa\u00e7ade systems <\/strong><\/span><\/h3>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"3. Irrigation technologies for rooftop and fa\u00e7ade systems"},"subContentId":"fcfc619a-c75f-45d5-ba6f-d0dac1cb2c10"},"useSeparator":"auto"},{"content":{"params":{"text":"
Once a reliable water source is identified, the next challenge lies in delivering it efficiently to crops\u2014especially in surface environments that lack natural drainage or consistent pressure. Rooftop and fa\u00e7ade-based agriculture requires irrigation systems that are lightweight, modular, and adapted to variable exposure. The goal is to maintain optimal moisture levels without overloading substrates, overusing water, or causing runoff.<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"3. Irrigation technologies for rooftop and fa\u00e7ade systems"},"subContentId":"0b919f0a-7fb7-4f8f-8757-2d351ea37a1e"},"useSeparator":"auto"},{"content":{"params":{"iconType":"icon","icon":"info","color":"#0eb50e","hotspots":[{"position":{"x":13.461538461538462,"y":13.698818356691397},"alwaysFullscreen":false,"content":[{"params":{"text":"
Drip systems are among the most effective irrigation methods for rooftop settings. These systems use low-pressure tubing with emitters that release small amounts of water directly to the base of each plant. Their advantages inclu 3. Irrigation technologies for rooftop and fa\u00e7ade systemsde:<\/p>\n\n
\n\t
High water-use efficiency (up to 90%)<\/li>\n\t
Reduced evaporation losses<\/li>\n\t
Compatibility with timers and moisture sensors<\/li>\n\t
Minimal wetting of foliage (important for food safety)<\/li>\n<\/ul>\n\n
Drip irrigation is particularly suitable for planter boxes, hydroponic troughs, and grow bags, and can also be integrated into fa\u00e7ade-mounted vertical systems with stacked emitters or micro-sprinklers.
\n
\nAs highlighted in the FAO\u2019s guide (2019) , drip systems can be made low-cost and adapted to local conditions using recycled plastic tubing and gravity-fed tanks, which is an approach promoted in many community-led rooftop gardens.<\/p>\n"},"library":"H5P.Text 1.1","metadata":{"contentType":"Text","license":"U","title":"Drip irrigation"},"subContentId":"85cbd714-b5b5-4228-8dca-566f1cb470e7"}],"header":"Drip irrigation"},{"position":{"x":37.25961538461539,"y":85.12512022533663},"alwaysFullscreen":false,"content":[{"params":{"text":"
Capillary systems, including self-watering planters and wick irrigation, are effective in contexts where water needs to be supplied without complex infrastructure. These passive systems use capillary action to draw water from a reservoir beneath the growing container into the root zone.<\/p>\n\n
\n\t
They are highly suitable for:<\/li>\n\t
Balconies and terraces<\/li>\n\t
Educational rooftop installations<\/li>\n<\/ul>\n\n
Crops with steady, moderate moisture needs (e.g., herbs, lettuces)
\nTheir low-tech, low-maintenance nature makes them ideal for urban settings with intermittent water access, or where automation is not feasible.
\n <\/p>\n"},"library":"H5P.Text 1.1","metadata":{"contentType":"Text","license":"U","title":"Capillary and wick systems"},"subContentId":"990a59a3-b71f-4fba-8c36-233b46a9bc34"}],"header":"Capillary and wick systems"},{"position":{"x":60.9375,"y":13.96803723550426},"alwaysFullscreen":false,"content":[{"params":{"text":"
Hydroponic systems used on rooftops and fa\u00e7ades often operate in closed-loop circuits, where water and nutrients are recirculated continuously. This reduces waste and allows for precise control over pH, nutrient levels, and oxygenation.
\nTypical system types include:<\/p>\n\n
\n\t
Nutrient Film Technique (NFT)<\/li>\n\t
Deep Water Culture (DWC)<\/li>\n\t
Ebb and Flow systems<\/li>\n<\/ul>\n\n
These systems are lightweight and productive, but require pumps, filtration units, and reservoir tanks, making them better suited for sites with stable electricity and technical oversight.
\n <\/p>\n"},"library":"H5P.Text 1.1","metadata":{"contentType":"Text","license":"U","title":"Hydroponic recirculation"},"subContentId":"b1313197-4dab-4a7c-9b9a-ff9cc3473a6e"}],"header":"Hydroponic recirculation"},{"position":{"x":84.73557692307693,"y":85.26767312448474},"alwaysFullscreen":false,"content":[{"params":{"text":"
Smart irrigation technologies are increasingly integrated into urban rooftop farms to reduce labour needs and maximise efficiency. These include:<\/p>\n\n
\n\t
Moisture and temperature sensors<\/li>\n\t
Internet-of-Things (IoT) platforms for data tracking<\/li>\n\t
Automated valves and app-controlled timers<\/li>\n<\/ul>\n\n
While these technologies can be costly, they provide precision and can be connected to broader building automation systems. This integration is particularly valuable for commercial rooftop greenhouses or institutional buildings that manage energy, water, and agriculture as part of a circular design.<\/p>\n"},"library":"H5P.Text 1.1","metadata":{"contentType":"Text","license":"U","title":"Smart and automated irrigation"},"subContentId":"fbebd2b8-79cb-427e-9157-2c2aebdb5ca1"}],"header":"Smart and automated irrigation"}],"hotspotNumberLabel":"Hotspot #num","closeButtonLabel":"Close","disableScaling":false,"image":{"path":"images\/image-skh8j71x.png","mime":"image\/png","copyright":{"license":"U"},"width":1074,"height":581},"backgroundImageAltText":"3. Irrigation technologies for rooftop and fa\u00e7ade systems"},"library":"H5P.ImageHotspots 1.10","metadata":{"contentType":"Image Hotspots","license":"U","title":"3. Irrigation technologies for rooftop and fa\u00e7ade systems"},"subContentId":"7f7ee16e-78b8-4b12-9aef-b959c1061975"},"useSeparator":"auto"},{"content":{"params":{"text":"
4.Water storage, retention, and drainage solutions <\/strong><\/span><\/h3>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"4.Water storage, retention, and drainage solutions"},"subContentId":"e78adfd2-a66b-4265-8267-d4f29ca6e878"},"useSeparator":"auto"},{"content":{"params":{"text":"
Water infrastructure on rooftops and fa\u00e7ades must serve multiple purposes: storing water safely, delivering it effectively, and preventing structural damage caused by overflow, pooling, or unintended leakage. Unlike ground-based farms, surface agriculture must integrate water infrastructure in compact, elevated, and weather-exposed settings, often under strict load constraints.<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"4.Water storage, retention, and drainage solutions"},"subContentId":"acd95458-2467-411d-a350-e4d19ae89674"},"useSeparator":"auto"},{"content":{"params":{"iconType":"icon","icon":"check","color":"#0eb50e","hotspots":[{"position":{"x":60.21634615384615,"y":30.49097042135452},"alwaysFullscreen":false,"content":[{"params":{"text":"

\nRainwater harvesting and hydroponic systems both require water storage tanks. On rooftops, these tanks must be lightweight and compatible with the surface\u2019s load-bearing capacity (refer to Module 2 for structural considerations). The most common options include:<\/p>\n\n
\n\t
Slimline polyethylene tanks (UV-resistant, low weight)<\/li>\n\t
Modular stacking tanks or bladders (used in tight spaces)<\/li>\n\t
Elevated barrels or gravity-fed containers (for passive irrigation)<\/li>\n<\/ul>\n\n
Placement is critical: tanks should be located near the main cultivation zone to reduce pipe length, minimise pressure loss, and simplify refilling. Overflow lines must be connected to existing drainage systems or redirected into secondary use tanks.
\nIn urban installations like the Toit Potager experimental rooftop in Paris, rainwater is stored in compact cisterns integrated into the building\u2019s envelope, where it supplies container-based growing beds using low-pressure drip lines (AgroParisTech, 2022) [13] .
\n <\/p>\n"},"library":"H5P.Text 1.1","metadata":{"contentType":"Text","license":"U","title":"Storage tanks and reservoirs"},"subContentId":"9d70d081-7840-4e6f-8f4d-69598a5b2928"}],"header":"Storage tanks and reservoirs"},{"position":{"x":32.331730769230774,"y":53.31066044008106},"alwaysFullscreen":false,"content":[{"params":{"text":"
On impermeable surfaces, water can quickly evaporate or run off without being absorbed. Therefore, the choice of substrate or media is essential for maximising moisture retention without waterlogging. Lightweight media like coconut coir, peat-free compost blends, and expanded clay pellets are commonly used. These allow for water holding capacity while avoiding root rot or compaction.
\n
\nPlanters often include perforated bases or internal reservoirs to allow drainage while retaining some water \u2014 a principle known as \"sub-irrigation.\" Wicking beds and SIP (sub-irrigated planters) apply this principle effectively on balconies or narrow terraces.<\/p>\n"},"library":"H5P.Text 1.1","metadata":{"contentType":"Text","license":"U","title":"Water retention in substrates"},"subContentId":"5a8c51f4-22c8-4363-9fad-b2822725dcda"}],"header":"Water retention in substrates"},{"position":{"x":58.65384615384615,"y":81.4253077835306},"alwaysFullscreen":false,"content":[{"params":{"text":"
Efficient and safe water drainage is a non-negotiable element of rooftop systems. Without adequate drainage, irrigation or rainfall can cause:<\/p>\n\n
\n\t
Surface pooling that stresses plants<\/li>\n\t
Degradation of waterproof membranes<\/li>\n\t
Water leakage into interior building spaces<\/li>\n\t
Slippery walking surfaces or ice hazards in cold climates<\/li>\n<\/ul>\n\n
Solutions include:<\/p>\n\n
\n\t
Sloped trays or frames to direct runoff<\/li>\n\t
Gutter and downspout systems with overflow controls<\/li>\n\t
Drainage mats beneath planters to protect membranes<\/li>\n\t
Waterproof trays under vertical planters to collect drips<\/li>\n<\/ul>\n\n
Fa\u00e7ade systems also require careful drainage design: if left unchecked, leaking vertical modules can damage walls, stain fa\u00e7ades, or annoy residents below. Many commercial systems integrate gutter-style channels and internal pipes to return water to collection tanks at the base.
\n
\nProper water infrastructure design supports not only plant health, but also long-term system safety, durability, and building compliance \u2014 reinforcing the interconnected dynamics of rooftop agriculture explored throughout this module.<\/p>\n"},"library":"H5P.Text 1.1","metadata":{"contentType":"Text","license":"U","title":"Drainage and runoff management"},"subContentId":"03ad6d56-fc76-4222-a0d2-3c98f151178f"}],"header":"Drainage and runoff management"}],"hotspotNumberLabel":"Hotspot #num","closeButtonLabel":"Close","disableScaling":false,"backgroundImageAltText":"4.Water storage, retention, and drainage solutions","image":{"path":"images\/image-OZBcOGn2.png","mime":"image\/png","copyright":{"license":"U"},"width":1020,"height":610}},"library":"H5P.ImageHotspots 1.10","metadata":{"contentType":"Image Hotspots","license":"U","title":"4.Water storage, retention, and drainage solutions"},"subContentId":"e4395fd1-988d-4012-980e-ab2d84a200c9"},"useSeparator":"auto"},{"content":{"params":{"text":"
5. Circular approaches and case examples <\/strong><\/span><\/h3>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"5. Circular approaches and case examples"},"subContentId":"e6e7d6cc-a8cd-458b-b984-b09aa31add92"},"useSeparator":"auto"},{"content":{"params":{"text":"
Water systems on industrial surfaces\u2014especially rooftops and fa\u00e7ades\u2014are uniquely positioned to benefit from circular design strategies. Because they are isolated from natural soil and groundwater cycles, these systems must often manage their own water flows from source to discharge and reuse. This challenge also opens up innovative opportunities for integration with building services, resource recovery, and climate adaptation.<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"5. Circular approaches and case examples"},"subContentId":"a02fbc32-5ee4-4fbc-9816-99d2c1b2b5ad"},"useSeparator":"auto"},{"content":{"params":{"presentation":{"slides":[{"elements":[{"x":2.28310502283105,"y":4.509837082135407,"width":52.51141552511416,"height":9.01685551609448,"action":{"library":"H5P.AdvancedText 1.1","params":{"text":"
Water recirculation in hydroponic systems<\/span><\/h3>\n"},"subContentId":"2ac0f361-ebdb-45a0-bf40-28c4e27da26d","metadata":{"contentType":"Text","license":"U","title":"Water recirculation in hydroponic systems"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""},{"x":2.2831050228310503,"y":24.804103951744743,"width":36.51974885844749,"height":47.34765206606911,"action":{"library":"H5P.Image 1.1","params":{"decorative":false,"contentName":"Image","expandImage":"Expand Image","minimizeImage":"Minimize Image","alt":"Water recirculation in hydroponic systems","file":{"path":"images\/image-334VKeR0.png","mime":"image\/png","copyright":{"license":"U"},"width":908,"height":596}},"subContentId":"70731dfb-c9a3-438d-8701-cc06f2c3f27b","metadata":{"contentType":"Image","license":"U","title":"Water recirculation in hydroponic systems"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""},{"x":42.23744292237443,"y":13.529511246406223,"width":55.93607305936073,"height":81.17143018208468,"action":{"library":"H5P.AdvancedText 1.1","params":{"text":"
Hydroponic systems deployed on rooftops often operate in a closed loop, where the same nutrient-enriched water is recirculated through plants, filtered, and reused. This drastically reduces consumption and virtually eliminates discharge. Key components include:<\/p>\n\n
\n\t
A main reservoir with nutrient solution<\/li>\n\t
Pumps to circulate water through channels or troughs<\/li>\n\t
Mechanical and\/or biological filtration<\/li>\n\t
UV or ozone disinfection (optional, for pathogen control)<\/li>\n<\/ul>\n\n
According to Kissinger et al. (2021) [14], recirculating hydroponic systems can use up to 90% less water than conventional soil-based cultivation. When combined with solar energy and on-site composting, they form part of a fully circular rooftop food system.
\n <\/p>\n"},"subContentId":"6516bb29-7400-4ef8-982f-26aa4bb21ddf","metadata":{"contentType":"Text","license":"U","title":"Water recirculation in hydroponic systems"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""}],"slideBackgroundSelector":{},"keywords":[{"main":"Water recirculation in hydroponic systems"}]},{"elements":[{"x":2.28310502283105,"y":4.509837082135407,"width":52.51141552511416,"height":9.01685551609448,"action":{"library":"H5P.AdvancedText 1.1","params":{"text":"
Rainwater reuse loops<\/span><\/h3>\n"},"subContentId":"c65077de-3cae-46cd-9357-9c7c515ba8fd","metadata":{"contentType":"Text","license":"U","title":"Rainwater reuse loops"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""},{"x":2.28310502283105,"y":24.80410395174474,"width":37.66974885844749,"height":48.51457241107165,"action":{"library":"H5P.Image 1.1","params":{"decorative":false,"contentName":"Image","expandImage":"Expand Image","minimizeImage":"Minimize Image","alt":"Rainwater reuse loops","file":{"path":"images\/image-I7e6nXmD.png","mime":"image\/png","copyright":{"license":"U"},"width":908,"height":592}},"subContentId":"9cf56cb8-09c4-4448-abcb-5023482e2478","metadata":{"contentType":"Image","license":"U","title":"Rainwater reuse loops"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""},{"x":42.23744292237443,"y":20.294266869609334,"width":55.93607305936073,"height":72.15446192006314,"action":{"library":"H5P.AdvancedText 1.1","params":{"text":"
Rooftop gardens that integrate rainwater collection and reuse systems can significantly reduce their dependency on municipal water. The collected water can be filtered and used directly for:<\/p>\n\n
\n\t
Drip irrigation<\/li>\n\t
Nutrient mixing for hydroponics<\/li>\n\t
Cleaning surfaces and tools<\/li>\n\t
Emergency storage during dry seasons<\/li>\n<\/ul>\n\n
In some cases, greywater from sinks or showers is also diverted to rooftop constructed wetlands, which purify the water before redirecting it to planters. This model is used in pilot sites across Europe, including in parts of Rotterdam and Copenhagen.<\/p>\n"},"subContentId":"7beb5bc0-c6b9-4581-a416-ec46250c6f34","metadata":{"contentType":"Text","license":"U","title":"Rainwater reuse loops"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""}],"slideBackgroundSelector":{},"keywords":[{"main":"Rainwater reuse loops"}]},{"elements":[{"x":2.28310502283105,"y":4.509837082135407,"width":52.51141552511416,"height":9.01685551609448,"action":{"library":"H5P.AdvancedText 1.1","params":{"text":"
Case example: Dakakker, Rotterdam<\/span><\/h3>\n"},"subContentId":"14f3068d-7eec-489f-9761-67cb56152e3f","metadata":{"contentType":"Text","license":"U","title":"Rainwater reuse loops"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""},{"x":2.28310502283105,"y":18.039348328541628,"width":54.4777397260274,"height":72.15446192006314,"action":{"library":"H5P.Image 1.1","params":{"decorative":false,"contentName":"Image","expandImage":"Expand Image","minimizeImage":"Minimize Image","alt":"Case example: Dakakker, Rotterdam","file":{"path":"images\/image-FZkEOf3W.png","mime":"image\/png","copyright":{"license":"U"},"width":935,"height":627}},"subContentId":"2560db73-2110-453c-bd20-1ce97f3b936c","metadata":{"contentType":"Image","license":"U","title":"Case example: Dakakker, Rotterdam"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""},{"x":58.21917808219178,"y":24.804103951744743,"width":39.95,"height":63.134787755792324,"action":{"library":"H5P.AdvancedText 1.1","params":{"text":"
One of Europe\u2019s most iconic rooftop farms, Dakakker [15] (\"roof field\") sits atop a multi-story office building and combines rainwater harvesting, urban composting, solar energy, and drip irrigation in a fully integrated system. Crops include leafy greens, herbs, edible flowers, and bees. Rainwater is stored in tanks and used for all irrigation, while organic waste is composted on-site and reused in planters.
\nThe success of Dakakker highlights how rooftop agriculture can be a node in a broader circular city system, reconnecting water, nutrients, and space in a productive loop.<\/p>\n"},"subContentId":"807859ff-12b7-4176-ab54-9f380d20f0be","metadata":{"contentType":"Text","license":"U","title":"Rainwater reuse loops"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""}],"slideBackgroundSelector":{},"keywords":[{"main":"Case example: Dakakker, Rotterdam"}]},{"elements":[{"x":2.28310502283105,"y":4.509837082135407,"width":59.36073059360731,"height":9.014036867918147,"action":{"library":"H5P.AdvancedText 1.1","params":{"text":"
Fa\u00e7ade system example: \u00d8sterGro, Copenhagen<\/span><\/h3>\n"},"subContentId":"af739291-8a17-48a0-83ac-d7bb7a455ff9","metadata":{"contentType":"Text","license":"U","title":"Fa\u00e7ade system example: \u00d8sterGro, Copenhagen"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""},{"x":2.28310502283105,"y":16.367889959975194,"width":54.794520547945204,"height":80.20745250577822,"action":{"library":"H5P.Image 1.1","params":{"decorative":false,"contentName":"Image","expandImage":"Expand Image","minimizeImage":"Minimize Image","alt":"Fa\u00e7ade system example: \u00d8sterGro, Copenhagen","file":{"path":"images\/image-ZhrUkCEE.png","mime":"image\/png","copyright":{"license":"U"},"width":954,"height":707}},"subContentId":"b57b1592-60c7-43a8-93f0-17159f49cf76","metadata":{"contentType":"Image","license":"U","title":"Fa\u00e7ade system example: \u00d8sterGro, Copenhagen"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""},{"x":60.50228310502283,"y":33.81814081966289,"width":37.66415525114155,"height":40.585827836969386,"action":{"library":"H5P.AdvancedText 1.1","params":{"text":"
The \u00d8sterGro rooftop farm, part of the city's climate adaptation strategy [16], includes vertical systems that integrate drip irrigation fed by harvested rainwater. The vertical structures are aligned to maximise solar gain, while irrigation is controlled by soil moisture sensors. This ensures optimal plant growth while conserving water. <\/p>\n"},"subContentId":"06a81da7-8249-4281-a190-2fa6f09c40e7","metadata":{"contentType":"Text","license":"U","title":"Rainwater reuse loops"}},"alwaysDisplayComments":false,"backgroundOpacity":0,"displayAsButton":false,"buttonSize":"big","goToSlideType":"specified","invisible":false,"solution":""}],"slideBackgroundSelector":{},"keywords":[{"main":"Fa\u00e7ade system example: \u00d8sterGro, Copenhagen"}]}],"keywordListEnabled":true,"keywordListAlwaysShow":false,"keywordListAutoHide":false,"keywordListOpacity":90,"globalBackgroundSelector":{}},"override":{"activeSurface":false,"hideSummarySlide":false,"summarySlideSolutionButton":true,"summarySlideRetryButton":true,"enablePrintButton":false,"social":{"showFacebookShare":false,"facebookShare":{"url":"@currentpageurl","quote":"I scored @score out of @maxScore on a task at @currentpageurl."},"showTwitterShare":false,"twitterShare":{"statement":"I scored @score out of @maxScore on a task at @currentpageurl.","url":"@currentpageurl","hashtags":"h5p, course"},"showGoogleShare":false,"googleShareUrl":"@currentpageurl"}},"l10n":{"slide":"Slide","score":"Score","yourScore":"Your Score","maxScore":"Max Score","total":"Total","totalScore":"Total Score","showSolutions":"Show solutions","retry":"Retry","exportAnswers":"Export text","hideKeywords":"Hide sidebar navigation menu","showKeywords":"Show sidebar navigation menu","fullscreen":"Fullscreen","exitFullscreen":"Exit fullscreen","prevSlide":"Previous slide","nextSlide":"Next slide","currentSlide":"Current slide","lastSlide":"Last slide","solutionModeTitle":"Exit solution mode","solutionModeText":"Solution Mode","summaryMultipleTaskText":"Multiple tasks","scoreMessage":"You achieved:","shareFacebook":"Share on Facebook","shareTwitter":"Share on Twitter","shareGoogle":"Share on Google+","summary":"Summary","solutionsButtonTitle":"Show comments","printTitle":"Print","printIngress":"How would you like to print this presentation?","printAllSlides":"Print all slides","printCurrentSlide":"Print current slide","noTitle":"No title","accessibilitySlideNavigationExplanation":"Use left and right arrow to change slide in that direction whenever canvas is selected.","accessibilityCanvasLabel":"Presentation canvas. Use left and right arrow to move between slides.","accessibilityProgressBarLabel":"Choose slide to display","containsNotCompleted":"@slideName contains not completed interaction","containsCompleted":"@slideName contains completed interaction","slideCount":"Slide @index of @total","containsOnlyCorrect":"@slideName only has correct answers","containsIncorrectAnswers":"@slideName has incorrect answers","shareResult":"Share Result","accessibilityTotalScore":"You got @score of @maxScore points in total","accessibilityEnteredFullscreen":"Entered fullscreen","accessibilityExitedFullscreen":"Exited fullscreen","confirmDialogHeader":"Submit your answers","confirmDialogText":"This will submit your results, do you want to continue?","confirmDialogConfirmText":"Submit and see results","slideshowNavigationLabel":"Slideshow navigation"}},"library":"H5P.CoursePresentation 1.25","metadata":{"contentType":"Course Presentation","license":"U","title":"5. Circular approaches and case examples"},"subContentId":"f16ad228-8456-4a61-8236-3b34ee74570a"},"useSeparator":"auto"},{"content":{"params":{"text":"
Water management in industrial surface agriculture is not just a technical necessity\u2014it is a defining element that shapes the viability, productivity, and sustainability of rooftop and fa\u00e7ade-based growing systems. The absence of soil and limited physical space demands careful planning across every step of the water cycle: sourcing, delivery, retention, and reuse.<\/p>\n\n
This unit has shown that while surface-based agriculture operates under severe constraints\u2014such as exposure to heat and wind, lack of infiltration, and limited infrastructure\u2014it also provides unique opportunities for integrating circular approaches. Rainwater harvesting, hydroponic recirculation, greywater reuse, and passive irrigation systems all allow these farms to operate with minimal external input and maximum resource efficiency.<\/p>\n\n
As demonstrated by cases like Dakakker in Rotterdam and \u00d8sterGro in Copenhagen, the most successful rooftop systems are those that treat water not just as an input, but as a resource loop. These projects illustrate how water systems can be designed to interact synergistically with urban energy, food, and waste flows, contributing to both sustainability goals and practical operation.<\/p>\n\n
In the next unit, we will explore the material and waste flows that accompany surface agriculture\u2014from substrate choices and packaging to composting and circular material strategies\u2014further expanding the dynamic perspective introduced here.<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"5. Circular approaches and case examples"},"subContentId":"e38f287f-8485-4b30-8b3a-c32ec4513770"},"useSeparator":"auto"}]}

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Module 4: Dynamics of industrial surface agriculture

Module 4: Dynamics of industrial surface agriculture