Quantifying the stormwater runoff volume reduction benefits of urban street tree canopy

Author(s):  
William R. Selbig ◽  
Steven P. Loheide ◽  
William Shuster ◽  
Bryant C. Scharenbroch ◽  
Robert C. Coville ◽  
...  
Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 944 ◽  
Author(s):  
Chao Guo ◽  
Jiake Li ◽  
Huaien Li ◽  
Bei Zhang ◽  
Menghua Ma ◽  
...  

Rain gardens have recently been studied as important low-impact development (LID) facilities that play a critical role in runoff volume reduction and pollutant purification. Approximately 16–40 rainfall events were monitored from March 2011 to October 2017 in order to determine the running effect of three rain gardens with respect to runoff volume reduction and pollutant purification. In particular, running fate analysis of rain gardens is the key focus in this study. Combined analyses revealed three key points. Firstly, performance assessment demonstrated that rain gardens effectively cut inflow volumes through the filter media; when the confluence area ratio was 6:1–20:1 (confluence ratio = roof area or road/garden area) and the rainfall was approximately 2.8–39.9 mm, the runoff volume reduction rate ranged from 9.8% to 100.0%. However, the average annual runoff reduction rate presented an initially increasing and then gradually decreasing trend with monitoring time. Secondly, according to water quality data in 54 rainfall events, the annual average concentration removal rate of NH4+-N was relatively good, but generally decreased with monitoring time. The concentration removal rate of NO3−-N and total phosphorus (TP) is unstable; however, the removal rate of total suspended solids (TSS) is better than that of total nitrogen (TN). Combined with runoff reduction, the pollutant load reduction by rain gardens is greater than 50%, although this decreases with increasing monitoring time. Thirdly, through the study of 7-year running effect on runoff reduction and pollutant purification, the “three-stage purification (TSP) concept” (periods of purification growth, stability, and attenuation) with respect to pollutant load reduction processes was finally proposed, and a curve chart was drawn for pollutant load reduction and rain garden operating fate (the “P–F” curve chart).


2020 ◽  
Author(s):  
Mariana D. Baptista ◽  
Marco Amati ◽  
Tim D. Fletcher ◽  
Matthew J. Burns

Abstract It is increasingly recognised that urban trees can contribute to reducing stormwater runoff by intercepting and retaining a fraction of rainfall received. What is less studied is the translation of this to reduced pollutant loads being transferred to receiving streams, rivers, and water bodies. In this paper, we assess interception of two tree species (Eucalyptus microcorys and Ulmus procera) in an urban park. This data is used in simple water balance modelling to predict the environmental and economic benefit of reducing nitrogen loads to receiving waterways as a function of reduced runoff volume resulting from rainfall interception by urban trees on public land (21% of the catchment area). We use a highly urbanized catchment in Melbourne, Australia to demonstrate the impact of an urban forest dominated by deciduous trees, evergreen trees or a mixed tree canopy cover. We found that doubling the urban canopy cover in the catchment, while keeping the current mix ratio of deciduous and evergreen trees, could reduce annual runoff volume by 30 mm (92 MLyr−1). Using the prescribed values that developers must pay the local water authority for nitrogen treatment as a condition of new development, we calculate that this would deliver a nitrogen load removal benefit of AUD$ 200/tree. If only deciduous trees are planted the annual runoff reduction would decrease to 24 mm (73 MLyr−1) and increases to 37 mm (112 MLyr−1) if only evergreen trees are planted. This study highlights both the additional benefits of public street trees and the differences in deciduous and evergreen trees which should be accounted for by policy makers.


2021 ◽  
Vol 9 ◽  
Author(s):  
Rita Sousa-Silva ◽  
Elyssa Cameron ◽  
Alain Paquette

As the climate continues to warm and the world becomes more urbanized, our reliance on trees and the benefits they provide is rapidly increasing. Many cities worldwide are planting trees to offset rising temperatures, trap pollutants, and enhance environmental and human health and well-being. To maximize the benefits of planting trees and avoid further increasing social inequities, a city needs to prioritize where to establish trees by first identifying those areas of greatest need. This work aims to demonstrate a spatially explicit approach for cities to determine these priority locations to achieve the greatest returns on specific benefits. Criteria for prioritization were developed in tandem with the City of Joliette, Canada, and based on nine indicators: surface temperature, tree density, vegetation cover, resilience, tree size and age, presence of species at risk, land use type, socioeconomic deprivation, and potential for active transportation. The City’s preferences were taken into account when assigning different weights to each indicator. The resulting tree planting priority maps can be used to target street tree plantings to locations where trees are needed most. This approach can be readily applied to other cities as these criteria can be adjusted to accommodate specific tree canopy goals and planning constraints. As cities are looking to expand tree canopy, we hope this work will assist in sustaining and growing their urban forest, enabling it to be more resilient and to keep providing multiple and sustained benefits where they are needed the most.


2016 ◽  
pp. 196
Author(s):  
FLORENTHIUS AGUNG NUGROHO ◽  
INDUNG SITTI FATIMAH

ABSTRACTThe Benefit of Trees Canopy in Reducing RunoffCase Study: Border of Center Ciliwung River, Bogor MunicipalityBogor as one of Center Ciliwung Sub Region River flow has decreased the percentage of green open space from year to year (Bappeda 2007). Study area boundary is the border as far as 300 meters to the left and right side of Ciliwung River. The method of this research is to estimating the benefits of tree canopy using Quickbird satellite image of the city of Bogor in 2006 with the software ArcView GIS 3.2 extensions CITYgreen 5.4. The study includes comparisons between the percentage of built up area and green open space. Comparison of built up area and the largest area of green open space can be found in Tanah Sareal District, the ratio reached 2:1. While the smallest ratio can be found in the MiddleDistrict of Bogor (1:1). This means the ideal condition of river’s border are found in the Middle District of Bogor that can decreasing runoff well. The estimation of trees canopy benefits can be seen from the amount of runoff volume, it can be predicted that trees canopy in study area can reduce average ± 7,55% of runoff volume. This means that the conditions in the study area was still below the average standard riverine.


Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 701 ◽  
Author(s):  
John Roberts ◽  
Andrew Koeser ◽  
Amr Abd-Elrahman ◽  
Benjamin Wilkinson ◽  
Gail Hansen ◽  
...  

Urban forests are often heavily populated by street trees along right-of-ways (ROW), and monitoring efforts can enhance municipal tree management. Terrestrial photogrammetric techniques have been used to measure tree biometry, but have typically used images from various angles around individual trees or forest plots to capture the entire stem while also utilizing local coordinate systems (i.e., non-georeferenced data). We proposed the mobile collection of georeferenced imagery along 100 m sections of urban roadway to create photogrammetric point cloud datasets suitable for measuring stem diameters and attaining positional x and y coordinates of street trees. In a comparison between stationary and mobile photogrammetry, diameter measurements of urban street trees (N = 88) showed a slightly lower error (RMSE = 8.02%) relative to non-mobile stem measurements (RMSE = 10.37%). Tree Y-coordinates throughout urban sites for mobile photogrammetric data showed a lower standard deviation of 1.70 m relative to 2.38 m for a handheld GPS, which was similar for X-coordinates where photogrammetry and handheld GPS coordinates showed standard deviations of 1.59 m and the handheld GPS 2.36 m, respectively—suggesting higher precision for the mobile photogrammetric models. The mobile photogrammetric system used in this study to create georeferenced models for measuring stem diameters and mapping tree positions can also be potentially expanded for more wide-scale applications related to tree inventory and monitoring of roadside infrastructure.


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