Transcript Document
Cost Surface Model Mapping the cost of bulk infrastructure for eThekwini
Ken Breetzke & Brendan Magill
What is the CSM?
• A GIS-based application that enables planners (& engineers) to investigate the bulk infra spatial efficiencies of developing at various locations in the municipality. The model calculates estimated costs of providing bulk services to a low-cost housing development positioned at any location in the municipality. • The model creates a layer or ‘surface’ of costs.
Background:
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Low income housing in inaccessible peripheral locations. Low land cost. High bulk cost.
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Substantial excess capacities in central areas for certain engineering services and most social services.
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Need to densify more central/accessible areas to create thresholds for PT
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Development beyond the ‘urban edge’ is outstripping current infra capacity budget impacts, dev’t delays, dev’t in inappropriate areas.
Bulk infrastructure costs for 5 Year Housing Plan (assuming a full level of service for all projects) Most projects outside urban edge cost > R10- 20 000 / site for bulks Most projects inside urban edge cost < R5000 / site for bulks Waste water treatment excess capacity of 47 Ml in Urban Core = 235 000 EDUs Financial sustainability dictates more housing projects inside urban edge AND more projects inside the Urban Core
Areas costing < R10 000/site
Areas costing < R20 000/site
Areas costing < R30 000/site
Cost Surface Model 1. Purpose P & I Cluster ’s Infrastructure Plan Drivers Responses
e.g.
Travel Demand Management Plan Recycling Sector Issues e.g. Water Loss Service Standards Spatial Efficiencies
Cost Surface Model
Rural / Urban Inland / Coastal Deficit Demand Infrastructure Required
Results: Infrastructure costs in North
Results: Infrastructure costs in North
Results: Infrastructure costs in North
Results: Infrastructure costs in Outer West
Results: Infrastructure costs in Outer West
Results: Infrastructure costs in Outer West
Results: Combined infrastructure costs Direction of cost increase Proposed Dube Trade Port - an island of very high cost.
Results: Combined infrastructure costs/ Urban Edge What service level in outlying areas?
Urban edge Northern Growth Path?
Do we support growth in western suburbs & what service level?
Rural areas densifying Incrementally (land mgmt on ITB) Do we investigate densification opps centrally & enforce an Urban Edge?
Key factors: Needs of economy Livelihoods of the poor Environmental- CC Political-service stds?
Integration
Urban Development Line
Proposed Urban Development Line Based on: Water Sanitation Roads Electricity Stormwater) Urban / Rural Development & Services Non-urban Urban
4. Results: Daily cost of public transport to commuters (R/day)
4. Results: Land Value
Cost Surface Roll Out 5. Must infra costs determine where you develop?
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Backlogs R33 bn Capital Budget of R5bn Where do we get the money?
Borrow R1bn - 4% rates increase!
Non achievement of MDGs Housing- need 6X more budget to achieve 2014 Rural water- provision by 2015 (target 2008) Rural sanitation- provision by 2013 (target 2010) Rural elec- provision by 2022 (target 2012)
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Easy model for any muni to develop
Cost Surface Roll Out 5. The Way Forward
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Needs updates of data and costs and ‘ground truthing’ using actual project costs.
Input to development of infra endowment policy (i.e who pays: Developer or City?) Leap frogging.
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Used by Housing Unit as input to aiding improved locational choices for housing- phasing priority Being fed into SDF/SDP process to potentially reduce infra spend e.g. phasing of devt., urban/rural edge.
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Need for Development Path to be more clear to allow infra to be planned more strategically & to avoid ad hoc take-up of spare capacity without knowing when cost shocks will hit.
Show cllrs why devt in urban centres and along growth corridors is preferable to sprawl. If you have R1bn- give more people jobs & services by concentrating devt. Then good PT connects people to jobs. Plus more public hsg in better locations & higher densities. Service informal settlements in accessible locations Density vs Cost table to show why full services (eng & soc) at low density has high unit cost
Select Densification slides
South Africa’s main cities compare poorly with other cities of similar size
Density- how do we compare?
City Population Area (sq km) Density
Ahmadabad Buenos Aires Kanpur Pune Yokohama Jaipur Nairobi Busan Madrid Berlin Los Angeles Jeddah Johannesburg Abidjan Ankara Durban Cape Town 3,510,000 3,050,728 3,221,435 3,760,636 3,672,789 3,210,570 3,500,000 3,574,340 3,213,271 3,450,900 3,831,868 3,234,000 3,888,180 3,660,682 3,901,201 3,468,086 3,497,097 191 203 267 430 435 485 696 766 698 892 1,290 1,230 1,645 2,119 2,516 2,292 2,455 18,377 15,028 12,065 8,746 8,443 6,620 5,029 4,666 4,604 3,869 2,970 2,629 2,364 1,728 1,551 1,513 1,424
Country
India Argentina India India Japan India Kenya South Korea Spain Germany USA Saudi Arabia SA Cote d' Ivoire Turkey SA SA
May 2011 BLUE SKIES – THE CASE FOR HIGHER DENSITY
Density (du/ha) < 3 3 - 20 20 - 40 40 - 60 > 60 IRPTN Road Rail May 2011 Tongaat Clermont Kwadabeka INK Mpumulanga Pinetown South Umlazi Berea CBD
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High density on periphery Low density in accessible areas Long commuting distances since townships have no economic base & Core still dominant Umkomaas BLUE SKIES – THE CASE FOR HIGHER DENSITY
STRATEGIES IN SUPPORT OF HIGHER DENSITY
Locational Strategy – Increase in Dwelling Units thru Densification Current No. of Dwellin g Units Current Density (Gross) Proposed Density (Gross) Potential No. of Dwellings Increase
Within 400m of IRPTN Trunks in Urban Centres
70,462 13 40 218,680 148,218
Within 400m of IRPTN Trunks in Prime Corridors
24,522 3 40 336,640 312,118 Sub-Total 94,984 555,320 460,336
Within 2km of IRPTN Trunks in Urban Centres Within 2km of IRPTN Trunks in Wider Corridor
Sub-Total May 2011
296,525 98,168
394,693
17 3 25 25 442,600 964,325
1,406,925 BLUE SKIES – THE CASE FOR HIGHER DENSITY
146,075 866,157
1,012,232
STRATEGIES IN SUPPORT OF HIGHER DENSITY
Funding Strategy – Example of Row-House Costs vs Subsidy TWI-STOREY ROW HOUSE Outlay
Topstructure Infrastructure
TOTAL R
86 759 13 337
100 096 SUBSIDY Funding
Regular Housing Subsidy USDG Subsidy
TOTAL R
64 062 30 531
94 593
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Excludes land purchase.
2010 estimates for proposed scheme at Kenville.
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Excludes land purchase.
Assumes USDG & Regular Housing Subsidy can be continued.
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Therefore the critical factor is access to land in good locations at low/no cost i.e. Govt-owned land.
May 2011 BLUE SKIES – THE CASE FOR HIGHER DENSITY
CSM detailed methodology
Methodology: 5 800 Hexagons Covering the Entire Municipality Stormwater: Cost of Erosion Protection & Attenuation Measures Assume this Polygon to be developed as Low Cost Housing Water: Cost to Provide Supply to the Site, Storage & Treatment Capacity Sewage: Cost to Provide Connection to Site & Treatment Capacity Electricity: Cost to Provide Supply to Site & Substation Capacity Roads: Cost to Bring Access Road to the Site
Cost Surfaces Methodology
A. Bulk Wastewater Infrastructure
Capital Costs only
Conveyance Costs (i.e. Pipework)
Distance Buffers from Existing Infrastructure User has Scope to Specify:
“True Length” Correction Factor
Pipe Diameters & Unit Costs Pumpstation Capital Costs
Treatment Costs (i.e. Works Capacities)
Model indicates Available Treatment Capacity
User has Scope to Specify:
Sewage Generation per Dwelling Unit per Day
Costs to Provide Treatment Capacity average cost per site to provide treatment capacity
Cost Surfaces Pilot Study
B. Bulk Water Infrastructure
Capital Costs only
Supply Costs (i.e. Pipework)
Distance Buffers from Existing Infrastructure (Retic. & Trunks) User has Scope to Specify:
“True Length” Correction Factor Pipe Diameters & Unit Costs
Storage Costs (i.e. Reservoirs)
Model indicates Available Storage Capacity User has Scope to Specify:
Water Usage per Dwelling Unit per Day Days Storage Required Costs for Reservoir Construction
Treatment Costs (i.e. Works Capacities)
As for Reservoirs above (except “Days Storage”)
Cost Surfaces Methodology
C. Bulk Roads Infrastructure
Capital Costs only
Model Calculates Cheapest Route to Connect into Existing Network (i.e. it is not “Buffers Based”)
Considers Costs to Traverse Features like:
Highways Rivers Rail
Considers Obstructions where Roads cannot be Built (e.g. Hawaan Forest, Gorges, etc.)
User has Scope to Specify:
Route Determination Parameters (for the Machine)
Unit Costs of Roads & Intersections Instances to Construct Intersections
Cost Surfaces Methodology
D. Bulk Electricity Infrastructure
Capital Costs only
Conveyance Costs (i.e. transmission lines)
Distance Buffers from Existing Infrastructure
User has Scope to Specify:
“True Length” Correction Factor
Unit Cost per km of o/head trans. line
Substation Costs
Model indicates substation capacity and coverage ‘circles’
User has Scope to Specify:
Reach factor and substation costs (R15mill=132kV)
Load density per Dwelling Unit per day eg 2 kVA/du du density average cost per site to provide substation capacity
Cost Surfaces Methodology
E. Storm water Infrastructure
Capital Costs only
Model Calculates cost of storm water mitigation measures
Considers Costs of:
Local erosion protection (function of soil type-erodibility index, land steepness, rainfall)
down stream erosion protection (function of length & gradient of downstream critical water course)
storm water attenuation (function of base cost of dep & factor for position of development in the catchment)
User has Scope to Specify:
Base costs and most other inputs
4. Results: Infrastructure Cost Shocks- WW/SW/Water
4. Results: Infrastructure Cost Shocks- Roads
4. Results: Infrastructure Cost Shocks- Electricity
Cost Surface Model 4. Results
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Provides relative costs of servicing sites at a strategic level.
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It has its limitations. So cannot replace the need for detailed modelling of site by site infra impacts!
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Tool to compare costs of infra/land/transport
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An integrator across service units: - of servicing costs - of infrastructure spare capacities - of infrastructure cost shocks Use to ID new areas where devt may occur cheaply from infra perspective due to take-up of spare capacity
Cost Surfaces Methodology
D. Transportation Costs
Operating Costs only Total Transportation Costs (Not Subsidy Costs)
Capitalised with Discount Rate to Compare Apples with Apples (!?)
Utilises Origin / Destination Information in Traffic Zones Straight Line Routings only (an Approximation) User has Scope to Specify Parameters in order to Calculate Numbers of Busses Required on any Route & the Costs to Operate these Busses