For the design of the gravity-fed rainwater capture system, several patents were found that helped create guidelines for the design of the tank. Here, two patents are shown and discussed:
The first patent describes a rainwater collection and distribution system that collects rainwater from gutters directly mounted on to the edge of a roof. This system consists of a tank attached to a support member that is adapted to the ground, beneath the gutter of the roof. This patent also includes an overflow pipe member that is pulled through the wall of the tank in order to drain rainwater.
The second patent outlines a vertical temporary water collection system that redirects water from the gutter to a vertical storage near the wall, which is then transported to another tank if necessary.
This system was achieved by using vertical pipes attached to the gutter, capped at the bottom to store the water. Each unit can hold up to 8 gallons of rainwater. This design includes a cut-off valve at the base of the pipe fitted with a hose extension, using the hydrostatic pressure in the storage pipe to dispense water for use in the yard.
Miyawaki Forest Method
“Seeing the Forest for the Trees? An Exploration of the Miyawaki Forest Method in the UK.” H. Qi et al.
This peer-reviewed journal discusses the ‘Miyawaki Forest Method’ (MFM) as a method afforestation in urban areas in the United Kingdom (UK). MFM is an afforestation management method coined by Dr Akira Miyawaki. MFM is differentiated from traditional plantation methods by the procedure of ground preparation and dense tree arrangements, which leads to enhancement of tree growth and increased biological diversity. This paper focuses on the application of MFM methods in the UK, as there is very little research done on MFM in more temperate climates. Urban forests showed high potential for urban applications in locations such as parks, playgrounds, school yards and was found to be useful for carbon sequestration and storage, flood management, and its social benefits including reintroducing urban citizens to nature and improving well-being. However, there are concerns on high initial costs and ‘high tree mortality through competition’. MFM was found to be less effective and less feasible in rural areas as compared to urban climates.
“A comparative analysis of urban forests for storm-water management” M. A. Rahman, et al.
This paper is an extensive study on how the stock of trees and shrubs in urban forests reduce runoff and discusses how climate and tree species (functional types) influence uptake (‘partitioning of rainfall into uptake and runoff’). Through this study M. Rahman et al. investigate four main categories involved in storm-water management by peri-urban forests; interception, transpiration, soil infiltration, followed by reduction of runoff. Interception of water by tree roots is a crucial process as it is responsible for returning water to the atmosphere through evapotranspiration. Groundwater flow is regulated by stem flow and through-fall, water that is allowed to flow through the canopy, which allows for soil infiltration. This process, followed by transpiration allows for increased water-retention capacity. Compared to shrubs and grasses, trees were found to be the most effective land use, or type of biomass for flood control. Specifically, coniferous trees provided better protection on an annual scale in terms of interception and transpiration, and broadleaved species showed better results for soil infiltration.
Urban forests can be designed to mimic natural forest conditions where interception can be as large as 50%. The study showed that three main factors affect rainfall partition: nature and magnitude of rainfall, functional types of vegetation and weather conditions. Conifers were found to have 20-30% interception and evaporation of annual rainfall, while deciduous gave 10-20%, as well as mixed forests having 15-32%. This paper examined various climactic conditions over several continents and zones. In temperate zones with a dry winter climate, broadleaved deciduous and evergreen coniferous vegetation types were found to be the most effective at interception of stormwater. It was discerned that tree selection for runoff management should focus on interception and partitioning rates as well as transpiration. “Trees in urban watersheds can restore natural hydrologic regimes by higher amounts of interception, transpiration, and infiltration, and consequently, delay of runoff and capture of storm water compared to other types of vegetation”. It was also highlighted that developed root and canopy beds had the highest statistics and overall retention capacity.