scholarly journals Evapotranspiration Measurement and Estimation of Crop Coefficient for Native Plant Species of Green Roof in the Tropics

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1669
Author(s):  
Ming Fai Chow ◽  
Muhammad Fadhlullah Abu Bakar ◽  
Jee Khai Wong ◽  
Lloyd Ling
Keyword(s):  
Soil Moisture ◽  
Plant Species ◽  
Green Roof ◽  
Crop Coefficient ◽  
Green Roofs ◽  
P Value ◽  
Water Retention Capacity ◽  
Native Plant ◽  
Retention Capacity ◽  
Native Plant Species

Extensive green roof is one of the sustainable urban stormwater management alternatives to manage and mitigate the urban surface runoff. In order to implement green roofs more effectively, suitable plant species and substrate components for tropical climate must be identified. The aim of this study is to investigate the evapotranspiration (ET) behaviors in extensive green roofs based on different substrate types and local native plant species. Four green roof test beds containing pro-mixing pot and burn soils were each vegetated with Axonopus Compressus (grass) and Portulaca Grandiflora (sedum). A weather station with soil moisture sensors was installed to measure the weather and soil moisture data. The results showed that the mean ET rates for grass-pot soil, sedum-pot soil, grass-burn soil and sedum-burn soil were 1.32 ± 0.41 mm/day, 2.31 ± 0.72 mm/day, 1.47 ± 0.39 mm/day and 2.31 ± 0.43 mm/day, respectively. It is noted that environmental parameters such as ambient temperature, solar radiation and wind speed showed significantly positive relationship (p value < 0.01) with ET rates of green roofs except relative humidity. The crop coefficients (Ks) for the studied green roof plant species are estimated based on actual and reference evapotranspiration rates. The sedum planted in burn soil showed the highest crop coefficient (0.64), followed by sedum in pot soil (0.62), grass in burn soil (0.39) and grass in pot soils (0.37), respectively. The findings in this study also showed that substrate with better water retention capacity generally improved the Ks values.

scholarly journals Water Resilience by Centipedegrass Green Roof: A Case Study

Buildings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 141 ◽  
Author(s):  
Shuai Hu ◽  
Lijiao Liu ◽  
Junjun Cao ◽  
Nan Chen ◽  
Zhaolong Wang
Keyword(s):  
Soil Moisture ◽  
Green Roof ◽  
Green Roofs ◽  
Saturated Soil ◽  
Water Retention Capacity ◽  
Water Runoff ◽  
Retention Capacity ◽  
Runoff Reduction ◽  
Eremochloa Ophiuroides ◽  
Rain Events

Centipedegrass (Eremochloa ophiuroides) is a low-maintenance turfgrass. The first extensive green roof of centipedegrass was established in TongZhou Civil Squares in 2014. However, storm-water-runoff reduction, water-retention capacity, and plant-water requirements by a centipedegrass green roof has not yet been defined. The soil moisture dynamics, rainwater-retention capacity, runoff reduction, and plant evapotranspiration were investigated by simulated centipedegrass green roof plots, which were constructed in the same manner as the green roofs in TongZhou Civil Squares in 2018. The results showed that the centipedegrass green roof retained 705.54 mm of rainwater, which consisted 47.4% of runoff reduction. The saturated soil moisture was 33.4 ± 0.6%; the excess rainfall over the saturated soil moisture resulted in runoff. The capacity of rainwater retention was negatively related to the soil moisture before rain events and was driven by plant evapotranspiration. Drought symptoms only occurred three times over the course of a year when the soil moisture dropped down to 10.97%. Our results indicate that the rainwater retained in the soil almost met the needs of plant consumption; a further increase of rainwater retention capacity might achieve an irrigation-free design in a centipedegrass green roof.

Ten-year persistence of native plant species on a green roof in Northeast US

2017 ◽  
Vol 18 (3) ◽  
pp. 227-234
Author(s):  
Jessica D Lubell ◽  
Bryan Connolly ◽  
Kristina N Jones
Keyword(s):  
Plant Species ◽  
Green Roof ◽  
Native Plant ◽  
Native Plant Species ◽  
Northeast Us

scholarly journals Growth of Native Aromatic Xerophytes in an Extensive Mediterranean Green Roof as Affected by Substrate Type and Depth and Irrigation Frequency

HortScience ◽  
2013 ◽  
Vol 48 (10) ◽  
pp. 1327-1333 ◽  
Author(s):  
Maria Papafotiou ◽  
Niki Pergialioti ◽  
Lamprini Tassoula ◽  
Ioannis Massas ◽  
Georgios Kargas
Keyword(s):  
Plant Growth ◽  
Plant Species ◽  
Green Roof ◽  
Green Roofs ◽  
Native Plant ◽  
Substrate Type ◽  
Irrigation Frequency ◽  
Artemisia Absinthium ◽  
Grape Marc ◽  
Local Character

Green roofs could be a way to increase vegetation in the center of old Mediterranean cities. The need for conservation of local character and biodiversity requires the use of native plant species, whereas the deficiency of water, particularly in semiarid regions, requires the use of species with reduced irrigation needs. Moreover, the aged buildings lead to the use of lightweight green roof constructions. Therefore, research was undertaken to investigate the possibility of using three Mediterranean aromatic xerophytes, Artemisia absinthium L., Helichrysum italicum Roth., and H. orientale L., at an extensive green roof in Athens, Greece. Simultaneously, the possibility of using locally produced grape marc compost was investigated. Substrate type and depth and irrigation frequency effects on growth of these species were studied. Rooted cuttings were planted mid-May in plastic containers with a green roof infrastructure fitted (moisture retention and protection of the insulation mat, drainage layer, and filter sheet) and placed on a fully exposed third floor flat roof at the Agricultural University of Athens. Two types of substrates were used, grape marc compost:soil:perlite (2:3:5, v/v) and peat:soil:perlite (2:3:5, v/v, as a control), as well as two substrate depths, 7.5 (shallow) and 15 cm (deep), and two irrigation frequencies, sparse (5 or 7 days in shallow and deep substrate, respectively) and normal (3 or 5 days in shallow and deep substrate, respectively). Increased contents of macroelements, total phosphorus (P) and potassium (K) in particular, were recorded in the compost-amended substrate, whereas both substrates had similar physical properties. Plant growth was recorded from May to October. The deep compost-amended substrate, independent of irrigation frequency, resulted in taller plants with bigger diameter and aboveground dry weight in all species. However, a remarkable result was that shallow compost-amended substrate with sparse irrigation resulted in similar or even bigger plant growth of all plant species compared with deep peat-amended substrate with normal irrigation. Thus, all three species were found suitable for use in Mediterranean extensive or semi-intensive green roofs, whereas the use of grape marc compost in the substrate allowed for less water consumption and the reduction of substrate depth without restriction of plant growth at the establishment phase and the first period of drought.

scholarly journals Phosphorus and Metals Leaching from Green Roof Substrates and Aggregates Used in Their Composition

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 112 ◽  
Author(s):  
Agnieszka Karczmarczyk ◽  
Anna Baryła ◽  
Joanna Fronczyk ◽  
Agnieszka Bus ◽  
Józef Mosiej
Keyword(s):  
Heavy Metals ◽  
Green Roof ◽  
Green Roofs ◽  
Point Of View ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Batch Tests ◽  
Quality Literature ◽  
Materials Used ◽  
Runoff Quality

Green roofs are constructions made of different layers, each serving a dedicated function. Substrates and materials used in their composition are essential from the point of view of rainwater retention and plant development, but they may have an adverse effect on runoff quality. Literature studies show that phosphorus and heavy metals are of main importance. The total roofs area covered with green increased in the last years in cities as they are efficient in retention of rainwater and delaying of the runoff, therefore, protecting the cities against floods. As green roofs filtrate a significant amount of rainwater, materials used in substrates composition should be carefully selected to protect urban receivers against pollution. The aim of this study was to assess phosphorus and heavy metals leaching from different green roof substrates and their components with the focus on green roof runoff quality. Both commercially made green roof substrates and often used compounds (construction aggregates) were tested in laboratory batch tests for P, Cu, Ni, Cd, and Zn content in extracts. Based on the results of this study, it could be emphasized that a large part of commonly used construction aggregates can be a source of phosphorus, some also can release elevated values of nickel. Therefore, the materials should be carefully tested before use in the green roof substrate composition, not only for their physical properties reflecting water retention capacity, but also for chemical composition.

Innovative green roof with high water retention and durability

2019 ◽  
Author(s):  
Thomas Cornelius Buch-Hanser ◽  
Guangli Du ◽  
David John Duffus
Keyword(s):  
Water Retention ◽  
Green Roof ◽  
Water Reservoir ◽  
Green Roofs ◽  
High Water ◽  
Water Retention Capacity ◽  
Storm Events ◽  
Concrete Element ◽  
Retention Capacity ◽  
Roof System

<p>Given the rapid increase in urban populations, combined with the effects of climate change, cities are struggling to provide green spaces to address liveability as well as adaptability to new challenges. Water retention and bio-diversity are the main advantages of green roofs. There are, however, limitations to green roofs that impede their acceptance and proliferation. There is for example uncertainty on how much water they retain during major storm events. In terms of building technology, green roofs today aren’t robust, and the risk for leakage through the roof membrane is disproportionally high when compared to the cost. A newly developed innovative green roof system with high water retention capacity and high durability will be presented. The patented prefabricated technology incorporate insulation and membrane into a single concrete element, ensuring improved robustness, quickened building times and a long term durable product. Initial indications for pricing indicate that the system is price-neutral when compared with green roofs as they are built today. The optimized structural performance obtain same loadbearing capacity, as existing systems, in spite of the relatively increased space created for water reservoir, without compromising the insulation capacity, hence the new green roof system further contribute to increased sustainability.</p>

scholarly journals Green Roof Design Techniques to Improve Water Use under Mediterranean Conditions

Urban Science ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 14 ◽  
Author(s):  
Teresa Paço ◽  
Ricardo Cruz de Carvalho ◽  
Pedro Arsénio ◽  
Diana Martins
Keyword(s):  
Water Use ◽  
Green Roof ◽  
Green Roofs ◽  
Climatic Conditions ◽  
Native Plant ◽  
Additional Energy ◽  
Climate Conditions ◽  
Native Plant Species ◽  
Roof Design ◽  
Mediterranean Conditions

Green roof typology can vary depending on buildings structure, climate conditions, substrate, and plants used. In regions with hot and dry summers, such as the Mediterranean region, irrigation plays an essential role, as the highest temperatures occur during the driest period of the year. Irrigation might reduce the heat island effect and improve the cooling of buildings during this period, however, the added cost of maintenance operations and additional energy consumption could outrun the benefits provided by the project. Moreover, in situations where water is scarce or primarily channelled to other uses (e.g., domestic, agriculture or industry) during drought occurrence, it is advisable to implement green roof projects with the lowest use of water possible. The objective of the present work is to investigate solutions to optimize water use in green roofs under Mediterranean conditions, such as those of southern Europe. Two case studies are presented for Portugal, and potential techniques to reduce irrigation requirements in green roofs were tested. These addressed the use of native plant species, including the extreme type of a non-irrigated green roof (Biocrust roof) and techniques for plant installation. Plant drought tolerance was found to be an advantage in green roofs under these climatic conditions and, for the species studied, aesthetic value could be maintained when irrigation decreased.

scholarly journals Water balance study on green roof in Brazil

2020 ◽  
Vol 4 (4) ◽  
pp. 141-144
Author(s):  
Calheiros Herlane Costa ◽  
Silva Fernanda Gomes Gonçalves ◽  
Costa Luisa Silva ◽  
Silva Matheus Lins Macedo
Keyword(s):  
Water Balance ◽  
Rainy Season ◽  
Green Roof ◽  
Green Roofs ◽  
Dry Season ◽  
Water Retention Capacity ◽  
Water Runoff ◽  
Retention Capacity ◽  
Balance Study ◽  
Recovery Capacity

The present study aims to investigate the water balance in conventional and green roofs and also to monitor the development of peanut grass (Arachis repens Handro), relating the type of vegetation cover or not with its water retention capacity and, consequently, to obtain the coefficient of runoff for each scenario tested. The scenarios tested were: (1) conventional collection surface with fiber cement tile, (2) green roof structure with substrate and no plant, and (3) planted green roof. The rains incident on the roof were obtained for the city of Itajubá, in Minas Gerais, by the curve of i-d-f with 5min of duration and 5years of return period according to the recommendation of NBR 10844 (ABNT,1989). The volumes of storm water runoff and drained from the bottom of the roofs studied were collected in calibrated graduated containers. It was concluded that: the peanut grass showed satisfactory development and high recovery capacity; the peanut grass took only 1½ month to cover the entire roof; the coefficient of runoff of the green roof for intense rainy season was on average 0.569 and in the dry season it was 0.003. While the conventional roof presented average surface runoff coefficient of 0.995 for the rainy season and 0.901 for the dry season; the component of the green roof that contributed most to the rainwater retention was the substrate. Therefore, attention should be paid to the choice of substrate so that it can adequately grow the plant, retain rainwater and not contaminate the bottom drainage water of the roof that can be used for less noble uses.

scholarly journals Performance of Green Roofs for Rainwater Control

2020 ◽  
Author(s):  
A. Raimondi ◽  
G. Becciu
Keyword(s):  
Goodness Of Fit ◽  
Probabilistic Approach ◽  
Green Roof ◽  
Green Roofs ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Climate Conditions ◽  
Average Return ◽  
Roof Design ◽  
The Given

AbstractGreen roofs can be an effective tool for sustainable urban drainage, since they reduce and retain runoff by delaying its peak. Most studies analysing the retention capacity of green roofs are usually referred to a specific place and roof condition and do not consider the possibility that the roof could be partially pre-filled from previous rainfalls at the beginning of the given event. The aim of this paper is to develop an analytical probabilistic approach to evaluate green roof performance for stormwater control in terms of runoff that could be applied for different sites and climate conditions. To this end, the possibility that the green roof retention capacity could not be completely available owing to pre-filling from previous rainfall events has been considered and equations for an optimum green roof design, relating the runoff average return interval to the water retention capacity, have been proposed. The influence of parameters affecting the runoff process has been examined in depth and a case study to test the goodness of fit of the resulting equations has been developed.

Introduced and native plant species composition of vacant unmanaged green roofs in New York City

2020 ◽  
Vol 23 (6) ◽  
pp. 1227-1238
Author(s):  
Jason M. Aloisio ◽  
Matthew I. Palmer ◽  
Amy R. Tuininga ◽  
J. D. Lewis
Keyword(s):  
New York ◽  
New York City ◽  
Species Composition ◽  
Plant Species ◽  
York City ◽  
Green Roofs ◽  
Plant Species Composition ◽  
Native Plant ◽  
Native Plant Species
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