Preliminary Cost Benefit Analysis of Storm Surge Hazard Mitigation in the Tuamotu Islands: an overview Anna Rios Wilks

http://tinyurl.com/pvt8cmd

In order to assess the most efficient method of reducing storm surge damage on the low-lying Pacific Island atoll of Rangiroa, French Polynesia, a cost benefit analysis is conducted which compares the expected costs and benefits produced from 4 types of adaptation option.

Findings suggest that for the specific storm surge considered, the relocation of buildings away from the immediate beach line and the use of a sea wall produce far lower expected infrastructure damage reduction than the general elevation of buildings by 1 m or more. The analysis concludes that in this case the gradual implementation of elevated MTR buildings would be the most efficient method of risk reduction.

...

Rangiroa is one of the largest atolls in the world, measuring over 75 km in length and 25 km in width it holds 2,473 inhabitants in the two main villages alone (ISPF, 2007). The towns are located on small islets surrounding the lagoon. Critically the maximum width of these islets (between the ocean and the lagoon) is only a few hundred metres and they offer no high ground to which inhabitants could flee in the event of a storm surge (Damlamian et al., 2013). Consequently, cyclones and storm surges can have devastating effects on the community.

Although the government is constructing cyclone shelters which will protect inhabitants during such events, there are still great losses to infrastructure and property to be expected. This CBA seeks to inform policy makers of what might be the optimal method of further adapting to the risk of storm surges in order to reduce this damage. Numerous options exist that the Government could pursue to mitigate damage. Four types of options have been analysed so that a way forward can be identified:

• the construction of a sea wall,
• the use of anti-cyclonic MTR buildings (“kit houses”) elevated to 1.5 metres,
• the elevation of normal buildings to 1 m,
• the implementation of a setback zone1.

http://en.wikipedia.org/wiki/Tuamotus

When only the value of the reduction in damage to buildings is quantified in the benefit analysis, the benefit cost ratios for all adaptation options are still slightly below 1, implying that no option generates enough savings in reduced damage to buildings to cover their costs.

On the other hand, both the elevation and MTR options also generate benefits that were not quantified in this analysis such as the reduction in damage to household goods and reduction in post disaster losses to business and services that may otherwise see their stock or machinery inundated. Furthermore, it is likely that for all types of adaptation option, there would also be a reduction in damage from other smaller, more frequent events.

Consequently, it is likely that once these other elements are included, analysis will demonstrate that adaptation options which allow for elevation of buildings will provide an overall gain to society.

by Anna Rios Wilks
SOPAC Geoscience and Technology Division of SPC
The 30th Science, Technology and Resources Network (STAR) Conference, Rarotonga, Cook Islands - October, 2013 and
the 9th Pacific IslandsConference on Nature Conservation and Protected Areas, Suva,Fiji– December, 2013
Pacific Disaster Net www.PacificDisasterNet.org

Urban traffic externalities: quasi-experimental evidence from housing prices

http://www.cpb.nl/en/publication/urban-traffic-externalities-quasi-experimental-evidence-from-housing-prices

Abstract:
This paper exploits a quasi-experiment to value the benefits of reducing urban traffic externalities. As a  source of exogenous variation we use the opening of a new bypass in The Hague, the Netherlands, that  reduced traffic on a number of local streets, leaving others unaffected. We calculate the effect of the change in traffic nuisance on housing prices and find that a reduction of 50% in traffic density induces a 1% increase in housing prices on average. Reductions in traffic nuisance are valued much more positively when the traffic  density is already high. We do not find evidence of anticipation effects up to 3 years before the change.  Furthermore, our results indicate that traffic nuisance effects are likely to be biased in cross-sectional studies.

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http://en.wikipedia.org/wiki/The_Hague

The estimated elasticity of housing prices to traffic density is on average -0.02 for houses adjacent to the street; it is factor 2 to 4 smaller for houses located further away from the street. For houses located on very busy roads the effect of traffic density turns out to be much stronger: for streets with traffic flows above 15,000 cars per day an elasticity coefficient of -0.1 is estimated. Furthermore, we show that the total benefits of traffic nuisance reduction amount to some 8% of the reference costs of the bypass construction. 

...

The effect of the traffic density change reaches as far as 40 meters from the affected street. Column 2 of table 2 (baseline model) reports the elasticity of the prices of houses not adjacent to the street to be between -0.005 and -0.01.

 ...

One can compute the benefits of traffic nuisance reduction brought about by the bypass studied in this paper. Following a conservative approach that only accounts for the effects on houses adjacent to the affected streets, and takes the medium density elasticity of -0.02, the total local benefits for the houses in our dataset amount to 1.4 million euros in Leidschendam-Voorburg and 2.6 million euros in The Hague Mariahoeve.  Assuming that the houses in the dataset are a random sample from the housing stock, the total benefit of  reduced nuisance equals some 18 million euros.15 This is 3.5 million euros per kilometre bypass. To gain an insight into the relative importance of these benefits, we compare them with the reference construction costs of a two-lane bypass.16 Vos (2004) reports that a simple two-lane highway on ground level costs some 10 million euros per kilometre. Where tunnels and bridges are involved, as was the case with the bypass near The Hague, the cost easily quadruples to more than 40 million euros per kilometre (V&W, 2003). This simple calculation suggests that, for a bypass to be cost-efficient it must generate other benefits in addition to the reduction of urban traffic nuisance. For the bypass in our study an important benefit was the improved accessibility of The Hague.

by Ioulia Ossokina and Gerard Verweij
CPB Netherlands Bureau for Economic Policy Analysis
February 19, 2014
Keywords: Traffic externalities; Quasi-experiment; Housing market; Hedonic approach.

Using a Spreadsheet to Model Rain Barrel Efficiency and Cost Benefit for Homeowners

http://horttech.ashspublications.org/content/24/1/156.short

Summary:

By collecting rain from a roof during rain events and storing it in a barrel or cistern, homeowners can create an alternative water supply to irrigate their home gardens and landscaping that will not overpump the groundwater or increase the water bill. In this example, a typical home garden would be 400 ft² on which the homeowner plans to irrigate using a 55-gal heavy-duty plastic barrel with a spigot located near the bottom of the tank. The objective of this study was to develop a spreadsheet-based model using daily data to determine how the watering habits of home gardeners affect the amount of available supplemental irrigation water and cost savings using a typical 55-gal rain barrel, thus resulting in a more realistic cost-benefit analysis. The model allows for multiple, user-selected criteria such as the size of the barrel, number of barrels, harvest efficiency of the guttering system, size of the garden, the catchment area, and the watering habits of the homeowner (such as how many days without precipitation have occurred before they feel the need to water), which were used to develop seven different scenarios. To optimize rainwater use and cost benefits, the following parameters are recommended: catchment area of 600 ft², 90% harvest efficiency by reducing leaks and other problems with guttering and rain barrel, threshold of 0.10 inch for a wet day, minimum of only 2 dry days before using the water in the barrel, and one overflow barrel. In this case, a homeowner in Knoxville, TN, can harvest an average of 1,570 gal per season (range of 1,076–2,076 gal), at an average cost savings of $22, and thus recover the cost of the two barrels in 3–6 years.

 

http://www.epa.gov/region3/p2/what-is-rainbarrel.pdf

by Joanne Logan; Department of Biosystems Engineering and Soil Science, University of Tennessee, 2506 EJ Chapman Drive, Knoxville, TN 37996-4531
HortTechnology http://horttech.ashspublications.org
Volume 24, Number 1; February, 2014; pages 156-158