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Table 3. Basic Details of surveyed parks in Panaji including the current daily water supply and demand
.
The urban greenery fulfils both regulatory and cultural services through a variety of species of plants and trees, well-kept groundcover, hedge rows. It cany hold enormous quantities of carbon in their biomass and sequester carbon.
Their service of land surface temperature reduction and regulating many parameters of microclimate (urban climate regulation) are among the widely regarded regulatory ecosystem services (Chichilnisky and Heal, 1998; Ramaiah
and Avtar, 2019). In addition, their services in bioremediation through assimilation of excess nutrients, detoxification processes, purification of water and oxygenating the air are vital. As far cultural services, the urban green spaces
serve inspirational, therapeutic, recreational and tourism, biodiversity conservation motifs as well as science and educational interests.
Environmental benefits of UGS have been well documented, but they are often unclear, unquantified, and/or outweighed by potential costs. In view of this, a case study from Panaji India was undertaken for showcasing the
importance of treated water in sustainable management of UGS in Indian cities. It is a widely acknowledged fact that management of wastewater and pollution prevention in urban settings require a cost-effective approach. In view
of this, a study was undertaken by the GSES. Spectral indices and LULC changes were deduced and published earlier (Ramaiah et al 2020).
This presentation focusses on the results of the daily water requirement, carbon stocks and sequestration potential of different plant types (trees, hedge-plants and lawn/groundcover grass) in Mahavir Park, one of the largest parks in
Panaji city. These results are a part of many other analyses carried out. is to estimate water requirement in UGS (and carbon sequestration potential in this of the entire UGS) as per the main objective (below). Using this
information possible reduction in LST and ecological and societal benefits are highlighted .
To evaluate whether treated water from Panaji
sewage treatment facility could adequately meet the
water requirements of Panaji city’s 1.86 sq km UGS
area and the possible ecological regulatory
services/benefits met, in relation to some UN SDGs
Acknowledgements
Methodology Framework
Introduction
Objective
Study Area
Details of Sewage Treatment Facility and Treated Water Quality
Salient Observations
Concluding Remarks
Significance of Treated Water in RES
Manish Ramaiah is grateful to JASSO for Fellowship, Hokkaido University for
facilities, and Prof. Ram Avtar for valuable guidance and constant support.
An Ecological Assessment on Sustainable Enhancement of Regulatory Ecosystem Services from Urban Green Spaces Using Recycled WaterManish Ramaiah1 , Ram Avtar1,2
1Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan;2Faculty of Environmental Earth Science, Hokkaido University, Sapporo 060-0810, Japan.
Panaji City, Goa, India
Derivation of Daily Requirements of Water
Primary data: Mahavir Park 15◦29’47.31” N; 73 ◦49’07.91” E
Total area: 37199 m2
Trees: 3130 in 22101 m2 [27 spp]
Hedge-plants: >15 sp in 2700 m2
Groundcover: Paspalum 6400 m2
Derivation of ETOP
DRW of trees,
hedge plants,
groundcover
DRW Estimation
All of Panaji UGS
Day time
Night time
𝐸𝑇0 = 0.408∆ 𝑅𝑛 − 𝐺 + 𝛾 37
𝑇 + 273 𝑢2 𝑒𝑠 − 𝑒 ÷ ∆ + 𝛾 1 + 0.24𝑢2
𝐸𝑇0 = 0.408∆ 𝑅𝑛 − 𝐺 + 𝛾 37
𝑇 + 273 𝑢2 𝑒𝑠 − 𝑒 ÷ ∆ + 𝛾 1 + 0.96𝑢2
WRtr X No of trees in all of 1.86 Sq Km UGS
WRhp m-2 X Total area of hedge rows in UGS
WRgc m-2 X Total area of lawns in UGS
WRTr (Ld-1) = EToP×#PF× (*R × R × 3.14)
WRhp (L m-2d-1) = D X PF X EToP X Kd
WRgc= 4.57 Lpdm-2 (as per CIMIS)
Formulae
net radiation (Rn, MJ m−2h−1),
ground heat flux density (G, MJ m−2h−1),
psychrometric constant (, kPa K−1),
mean air temperature (T,◦C),
wind speed (u2, m s−1),
saturation vapor pressure (es, kPa),
vapor pressure (e, kPa),
slope of SVP at temp T (, kPa K−1)
WR=Water Requirement,
EToP = ETo Panaji,
Evapotranspiration (cm d-1);
PF=Plant Factor
Kd= Canopy density (=1.02)
21.60 sq km City area
1.860 sq km UGS area
0.784 sq km Lawn area
0.236 sq km Hedges area
0.538 sq km Trees area
Trees
67275
in UGS
Panaji City UGS details
#Two plant factors (0.6 for somewhat cooler Oct-Jan and 0.7 for warmer Feb-Jun periods) were used for calculating
tree DWR; *Canopy/crown radius of different tree species calculated on-site based estimations from Mahavir Park;
Coupling of carbon, water, and energy cycles is integral to impacts of urban vegetation on climate (Pataki et al., 2011).
This nexus will have much advantages when recycled water is reused. This is one of the important Sustainable
Development Goals of the UN. The two climate-regulating services of carbon sequestration involve direct removal of
carbon dioxide from the atmosphere and indirect effects of vegetation on local cooling through shading and transpiration
in warm climates (Livesley et al 2016)
The UGS are “purported to offset greenhouse-gas (GHG) emissions, remove air and water pollutants, cool local climate,
and improve public health.” (Pataki et al 2011). To make use of these services, the municipalities in the cities aspiring to
be “smart” especially in developing countries such as India have to focus efforts on designing and implementing
ecosystem-services-based “green infrastructure” in urban environments.
Even prior to Plato (c. 400 BC), there already was an awareness of ecosystems services supporting the humankind. The
earlier civilization was in the knowing that deforestation -in complex ways- could lead to soil erosion and drying of
springs. During the last 200 years, many modern ideas of ecosystem services have emerged. These developments have
continued to expand our knowledge of the intricate functional mechanisms that are at play. These developments must
inspire urban population to benefit through ecologically sustainable resource reuses.
Park Area(m2)
Trees(n)
HedgeArea (m2)
Lawn(m2)
CurrentSupply
(LPD)
Daily Water Requirement (Litres per Day. LPD)
Trees# Hedges Lawn Demand
Kala Academy 10630 250 360 2675 10000 5991.25 2437.20 12224.75 20653.20
NGRF Office Park 5000 290 160 2250 4800 6949.85 1083.20 10282.50 18315.55
SGRF office Park 6500 180 800* 1625 6000 4313.70 5416.00 7426.25 17155.95
Mahavir Park+Art Park 37211 3130 2700 6410 8400 75010.45 18279.00 29293.70 122583.20
Garcia da Orta Garden 4000 150 405 1500 15000 3594.75 2741.85 6855.00 13191.60
Ambedkar Park 10000 480 1620 6500 16000 11503.20 10967.40 29705.00 52175.60
Joggers Park 11500 400 2340 6900 16000 9586.00 15841.80 31533.00 56960.80
Total 84841 4880 8385 27860 76200 116949.20 56766.45 127320.20 301035.90#currently no direct watering of trees except for a small number nearer the hedge lanes or groundcover. Daily demand of water estimated at an
average of 24 litres per tree, *nursery plot including narrow access lanes for watering, nursing/caring
A key informant-based survey questionnaire was prepared and required details were sought from the offices of the sewage treatment plant located at
Tonca in Panaji City. The STP handles 15 MLD raw sewage daily and produces ca. 14 MLD treated water. Data on the quality of raw sewage received
and water quality achieved post-treatment were also obtained (Table 1) and the treated water outflow point shown below (Fig 1)
Parameters Tolerance limit Raw sewage Outlet values
Colour/odour - -- Clear, odorless
Suspended solids (mg.l-1) 100 400 10
Particle size suspended solids units <850 u. 140 5
Dissolved inorganic solids max. (mg.l-1) 2100 480 246
pH 5.5 – 9.0 6.88 7.56
Oil and grease. Max. (mg.l-1) 10 86 NA
Ammoniacal nitrogen as N. Max. (mg.l-1) 50 74 NA
Total Kjeldahi nitrogen as N. Max. (mg.l-1) 100 28 NA
BOD5 at 20 Max. (mg.l-1) 30 540 33
COD. Max. (mg.l-1) 250 960 64
Mercury as Hg. Max. (mg/l) 0.01 0.097 BDL
Lead as Pb. Max. (mg.l-1) 0.1 0.035 0.002
Hexavalent chromium as Cr0+ Max. (mg.l-1) 0.1 0.147 NA
Zinc as Z. Max. (mg.l-1) 5 0.369 0.008
Nickel as Ni Max. (mg.l-1) 3 0.214 0.08
Chloride as Cl. Max. (mg.l-1) 1000 2400 20
Dissolved phosphate as P. Max. (mg.l-1) 5 14 0.01
Sulphate as SO4 Max. (mg.l-1) 1000 550 11
Sulphide as S. Max. (mg.l-1) 2 5 0.8
Coliform count number/100ml 25 to <60/100ml 240x106 Nil to 40
Fig 1. Recycled water outflow point. The safety
limits achieved are listed in Table 1. A few WQ
Indicator ones depicted in Fig 3 later
Water Requirements of Trees in Mahavir Park: It is evidenced that daily water requirement (DWR) is different for different
species solely based on the canopy area/diameter of a given species of tree. The DWR of 3130 trees in Mahavir Park (Fig 2 a-c)
during Oct-Jan period is 79346 litres (on an average of 25.35 litres/tree). During Feb-June, the total volume of water required is
92570 litres (average 30 litres/tree). Larger the canopy area, higher was the volume of water required. For hedge plants in an area of
2700 m2, @6.77 litres (calculated per the formula given above) the DWR is 18280 litres and for groundcover in an area of 6400 m2
@ 4.57 Litres 29248 litres. But the water applied in the park is only 8400 litres. It is to be noted that trees are not watered at all. Thus
there is very high water-stress for both hedge rows and groundcover.
0
200
400
600
Samanea
saman
Delonix regia Tamarindus
indica
Inga dulcis Terminalia
catappa
Lagerstroemia
speciosa
(a) DWR of Larger Trees (>125 m2 CA) Mahavir Park, Panaji
Canopy area (m2)
DWR Oct-Jan (Ld-1)
DWR Feb-Jun (Ld-1)
0
20
40
60
80
100
Syzygium
cumini
Peltaphorum
pterocarpum
Spatodea
companulata
Alstonia
scholaris
Mimusops
elengi
Sapindus
mukorossi
Mammea
suriga
Acacia
auriculiformis
C. pulcherima Bauhinia
purpurea
Tecoma
capensis
Cassia
javanica
(b) DWR of Medium Sized Trees in Mahavir Park, Panaji
Canopy area (m2)
DWR Oct-Jan (Ld-1)
DWR Feb-Jun (Ld-1)
0
10
20
30
40
50
Millettia
pinnata
Dypsis
lutescens
Butea
monosperma
Mussaenda
erythrophylla
Casuarina
equisetifolia
Cassia fistula Phyllantus
emblica
Hyophorba
lagenicaulis
Polyalthia
longifolia
Ca
no
py
are
a M
2o
r D
WR
(L
)
Tree species
(c) DWR of Small Sized Trees in Mahavir Park, Panaji
Canopy area (m2)
DWR Oct-Jan (Ld-1)
DWR Feb-Jun (Ld-1)
Lit
res
or
m2
Fig 2. Canopy areas of larger (a), medium (b), and smaller (c) sized trees in Mahavir Park in Panaji, Goa, and their daily requirement of water (L d-1)
10
25
33
64
1 11 4
SS TDS BOD COD Nitrate Sulphate Coliforms
Conce
ntr
atio
n(m
g^-1
)
Parameters
Treated water characteristics
Fig 3 Post-treatment characteristics of some important water
quality indicator parameters of out-falling treated water.
(Coliform counts are numbers, other parameters in mg l-1
concentrations).
In all routinely parameters, monitored by the facility, the
safe dischargeable limits are achieved routinely
Following Results Used for Estimating the DWR of all Parks in Panaji
DWR (Litres) for trees @ 27.18 L d-1 tree-1 = 3130*27.18 = 85074
DWR (litres) for hedge plants (HP) in 2700 m2 @6.77 L m2 = 18279
DWR (L)m for groundcover (GC) in 6410 m2 @4.57 Lm2= 29294
The water currently supplied only to HP and GC is only 8400 litres
ParametersPrimary data from 7
Surveyed Parks#
Estimates for the whole
Panaji UGS
City area Km2 21.60
UGS area; Km2 (% of city area) 1.858 (8.60%)
Hedge plants area (@12.72% of UGS, m2 8385 236000
Groundcover area (@ 42.23% of UGS; m2 25860 784000
Water used in UGS (MLD) 0.0762 2.66*
Hedge-plant DWR @ 6.77L m-2 (MLD) 0.057 1.599
Groundcover DWR @ 4.57Lm-2 (MLD) 0.012 3.585
Total DWR (MLD) 0.11 5.184
% DRW shortage hedge + groundcover 49.60 51.30
DRW @ for hedge + ground cover (MLD) 0.184 5.185
Trees area in ha 3.25 53.82
No of trees [@ 1 tree in 8 (±13) m-2] 4880 67275
Average DWR/tree @ 23.87L (MLD) 0.117 1.606
Trees’DWR % of available treated water 15.25 (of 14 MLD available)
In all seven parks, the daily of water requirement of hedge plants and groundcover is not fully met. But, the volume of treated water
of 14 MLD drained out from the STP exceeds the daily water demand by over 50%. Therefore, this water can be diverted for use in
the UGS. By doing so, the following are the major ecological benefits are possible. By making use of the regional
evapotranspiration rates of 8.89 mm-1 d-1 for Panaji can help to recognise the importance of UGS for example in achieving urban heat
balance and other advantages. Quantitative data (unpublished results) is worked for points 3-5 in Fig 4.
Urban Green Space ecosystem service and
function (Figure from Livesley et al 2016)Picture from Dr Ambedkar Park, Panaji, Goa.
A good proportion of regular staff is women.
Many Known Regulatory
Ecosystem Services of UGS
can be ENHANCED
by Using Treated Water
Available in All Good Cities
References:• Chichilnisky, G., & Heal, G. (1998). Economic returns from the biosphere. Nature, 391(6668), 629–630. https://doi.org/10.1038/35481
• Livesley, S. J., McPherson, E. G., & Calfapietra, C. (2016). The Urban Forest and Ecosystem Services: Impacts on Urban Water, Heat, and Pollution Cycles at the Tree, Street, and City Scale. Journal of Environmental
Quality, 45(1), 119–124. https://doi.org/10.2134/jeq2015.11.0567
• Norton, B. A., Coutts, A. M., Livesley, S. J., Harris, R. J., Hunter, A. M., & Williams, N. S. (2015). Planning for cooler cities: A framework to prioritise green infrastructure to mitigate high temperatures in urban landscapes.
Landscape and Urban Planning, 134, 127–138.
• Pataki, D. E., Carreiro, M. M., Cherrier, J., Grulke, N. E., Jennings, V., Pincetl, S., Pouyat, R. V., Whitlow, T. H., & Zipperer, W. C. (2011). Coupling biogeochemical cycles in urban environments: Ecosystem services, green
solutions, and misconceptions. Frontiers in Ecology and the Environment, 9(1), 27–36. https://doi.org/10.1890/090220
• Ramaiah, M., & Avtar, R. (2019). Urban Green Spaces and Their Need in Cities of Rapidly Urbanizing India: A Review. Urban Science, 3(3). https://doi.org/10.3390/urbansci3030094
• Ramaiah, M., Avtar, R., & Rahman, Md. M. (2020). Land Cover Influences on LST in Two Proposed Smart Cities of India: Comparative Analysis Using Spectral Indices. Land, 9(9). https://doi.org/10.3390/land9090292
Regulatory ecosystem services achievable using treated water for UGS Sustenance
Treated
Water-Use
Aided
Regulatory
Ecosystem
Services
1 Recycled water for trees
Balances urban heat (LST)
5 Improves employment opportunities
Including women and frail persons
3 compensates partially the
evapotranspiration losses
2 Reduces/eliminates
groundwater extraction:
6 Enhanced thermal comfort,
shading; added tourist attraction
4 Aids stress-free plant growth
Enhances carbon storage.
Fig 4. Qualitative assessment on the advantages offered by the treated water use in UGS which helps RES