title: Willingness-to-Pay for prescribed fire in the Colorado (USA) Wildland Urban Interface

authors: Kaval, Pamela

subjects: prescribed burning

abstract: During the summer of 2001, survey data were collected from Colorado residents living near public lands (i.e., the wildland urban interface). Data were collected by telephone after mailing respondents a survey. These data include detailed information of respondents’ views towards wildfire management and willingness-to-pay (WTP) values for prescribed burning. Results indicate that Colorado residents living near public lands are aware that fire is a natural process in their area and are in favor of using prescribed burning for fire risk reduction. They also are willing-to-pay an annual tax for prescribed fire undertaken on the public lands near their homes. Respondents’ support for adopting a fire risk mitigation policy based on prescribed fire depended on perceived fire frequency intervals. The substantial WTP values for prescribed burning indicate that the public living in the wildland urban interface could potentially pay an annual tax, so the burden of wildfire management need no longer predominantly lie in the hands of the general taxpayers.

text: Willingness-to-Pay for prescribed fire in the Colorado (USA) Wildland Urban Interface During the summer of 2001, survey data were collected from Colorado residents living near public lands (i.e., the wildland urban interface). Data were collected by telephone after mailing respondents a survey. These data include detailed information of respondents’ views towards wildfire management and willingness-to-pay (WTP) values for prescribed burning. Results indicate that Colorado residents living near public lands are aware that fire is a natural process in their area and are in favor of using prescribed burning for fire risk reduction. They also are willing-to-pay an annual tax for prescribed fire undertaken on the public lands near their homes. Respondents’ support for adopting a fire risk mitigation policy based on prescribed fire depended on perceived fire frequency intervals. The substantial WTP values for prescribed burning indicate that the public living in the wildland urban interface could potentially pay an annual tax, so the burden of wildfire management need no longer predominantly lie in the hands of the general taxpayers.

year: 2006-10

title: Risk analysis associated with flank failure from Putauaki, Bay of Plenty, New Zealand

authors: Hewitt, Dolan

subjects: volcanic landslides

abstract: Volcanoes are dynamic evolving structures, with life cycles that are punctuated by episodes of
flank instability. Putauaki (Mount Edgecumbe) is a stratovolcano located onshore in the Bay of
Plenty, New Zealand. The aim of this study was to assess the stability of Putauaki and analyse the risk associated with volcanic collapse. To achieve this objective, a multidisciplinary approach was used, incorporating geomorphological and geological mapping, rock mass classification,
laboratory testing to identify geotechnical properties of materials representative of the volcano,
stability modelling, and analysis of landslide run-out zones.
Putauaki comprises two predominant features including the larger and younger Main Cone (the
summit lying 820 m a.s.l., slope angles up to 36 ), and smaller and older Main Dome (the summit
lying 420 m a.s.l., slope angle of 24 ). Both features show little evidence of erosion or surface
water. Rock mass description defined six lithotechnical units including indurated andesite,
indurated dacite, scoriaceous andesite, altered andesite (all categorised as hard rocks), and block
and ash flow and Matahina Ignimbrite (both categorised as soft rocks). The uniaxial compressive
strength (UCS) of indurated andesite and indurated dacite was 60   4 MPa and 44.7   0.9 MPa
respectively, correlating with moderately strong rock. Discontinuities of the indurated units were
widely spaced, showed medium persistence and wide aperture, and were slightly weathered. Infill
comprised predominantly loosely packed, very strong, coarse gravel. UCS of scoriaceous andesite
and altered andesite was 25   5 MPa and 15   1 MPa respectively, allowing categorisation as very
weak rock. Discontinuities of scoriaceous andesite were widely spaced, showed high persistence
and wide aperture, and were moderately weathered. Discontinuities of the altered andesite were
moderately spaced, showed low persistence and wide aperture, and were highly weathered. Infill
of scoriaceous and altered andesite was loosely packed, moist, weak to very weak medium gravel.
The block and ash flow was a poorly sorted, loosely packed, sandy, gravely and cobble rich matrix
supported deposit. The Matahina Ignimbrite was a very weak, discontinuity-poor deposit. Shear
box testing indicated cohesion and friction angle of 0 MPa and 42.1  (block and ash flow) and 1.4
x 10-3 MPa and 41.7  (Matahina Ignimbrite) respectively. These values are similar to published
values. Correlation of each lithotechnical unit to its respective rock mass description site allowed
approximate boundaries of each unit to be mapped.
Each unit's mass strength was combined with measured bulk densities and incorporated into two
dimensional slope profiles using the stability modelling package GalenaTM. Ten slope profiles of
Putauaki were constructed. Failure surfaces for each slope profile were defined using the Bishop
simplified multiple analysis method. Four slope profiles showed the potential for small scale
failure (less than 0.1 km2 of material). The remaining six slope profiles showed the potential for large
scale failure (greater than 0.1 km2 of material). Stability of these six slope profiles was investigated further
in relation to earthquake force, watertable elevation, and a disturbance factor of the rock mass (D).
Conditions of failure graphs for profile 6a showed that at low D (less than 0.4), earthquake forces and
watertable elevation must be unrealistically high for the region (greater than 0.33 g; greater than 15% watertable
elevation) in order produce a factor of safety less than 1. The remaining five slope profiles showed
potential to be unstable under realistic earthquake forces and watertable elevations. Two of these
profiles were unable to achieve stability at D greater than 0.8 (profile 4) and D greater than 0.9 (profile 5). A D value
of 0.6 (intermediate between 0.4 and 0.8) is argued to most realistically represent Putauaki. The
fact that Putauaki has not undergone large scale failure to date supports the conclusion that the
constructed models overestimate the influence of those factors which promote slope instability.
Maximum and minimum landslide run-out zones were constructed for the slope profiles exhibiting
the potential for large scale failure. Definition of the position and extent of maximum and
minimum run-out zones assumed H/L (fall height to run-out length) ratios of 0.09 and 0.18
respectively, as well as the 'credible flow path' concept. Identified impacts of landslides sourced
from Putauaki include inundation of Kawerau Township, Tarawera River, forestry operations, road
networks, and power supplies. Based on these impacts, the risk posed by landslides from each
slope profile was categorised as ranging from relatively low to relatively high. Landslides sourced from the south-west flanks pose a relatively low risk due to their prerequisite of unrealistically
high watertable elevations and earthquake forces. Landslides sourced from the north-west flanks pose a relatively high risk as minimum run-out will inundate north-east parts of Kawerau
Township. Landslides sourced from the eastern flanks pose a moderate risk due to their run-out
zones avoiding Kawerau Township.

text: Risk analysis associated with flank failure from Putauaki, Bay of Plenty, New Zealand Volcanoes are dynamic evolving structures, with life cycles that are punctuated by episodes of
flank instability. Putauaki (Mount Edgecumbe) is a stratovolcano located onshore in the Bay of
Plenty, New Zealand. The aim of this study was to assess the stability of Putauaki and analyse the risk associated with volcanic collapse. To achieve this objective, a multidisciplinary approach was used, incorporating geomorphological and geological mapping, rock mass classification,
laboratory testing to identify geotechnical properties of materials representative of the volcano,
stability modelling, and analysis of landslide run-out zones.
Putauaki comprises two predominant features including the larger and younger Main Cone (the
summit lying 820 m a.s.l., slope angles up to 36 ), and smaller and older Main Dome (the summit
lying 420 m a.s.l., slope angle of 24 ). Both features show little evidence of erosion or surface
water. Rock mass description defined six lithotechnical units including indurated andesite,
indurated dacite, scoriaceous andesite, altered andesite (all categorised as hard rocks), and block
and ash flow and Matahina Ignimbrite (both categorised as soft rocks). The uniaxial compressive
strength (UCS) of indurated andesite and indurated dacite was 60   4 MPa and 44.7   0.9 MPa
respectively, correlating with moderately strong rock. Discontinuities of the indurated units were
widely spaced, showed medium persistence and wide aperture, and were slightly weathered. Infill
comprised predominantly loosely packed, very strong, coarse gravel. UCS of scoriaceous andesite
and altered andesite was 25   5 MPa and 15   1 MPa respectively, allowing categorisation as very
weak rock. Discontinuities of scoriaceous andesite were widely spaced, showed high persistence
and wide aperture, and were moderately weathered. Discontinuities of the altered andesite were
moderately spaced, showed low persistence and wide aperture, and were highly weathered. Infill
of scoriaceous and altered andesite was loosely packed, moist, weak to very weak medium gravel.
The block and ash flow was a poorly sorted, loosely packed, sandy, gravely and cobble rich matrix
supported deposit. The Matahina Ignimbrite was a very weak, discontinuity-poor deposit. Shear
box testing indicated cohesion and friction angle of 0 MPa and 42.1  (block and ash flow) and 1.4
x 10-3 MPa and 41.7  (Matahina Ignimbrite) respectively. These values are similar to published
values. Correlation of each lithotechnical unit to its respective rock mass description site allowed
approximate boundaries of each unit to be mapped.
Each unit's mass strength was combined with measured bulk densities and incorporated into two
dimensional slope profiles using the stability modelling package GalenaTM. Ten slope profiles of
Putauaki were constructed. Failure surfaces for each slope profile were defined using the Bishop
simplified multiple analysis method. Four slope profiles showed the potential for small scale
failure (less than 0.1 km2 of material). The remaining six slope profiles showed the potential for large
scale failure (greater than 0.1 km2 of material). Stability of these six slope profiles was investigated further
in relation to earthquake force, watertable elevation, and a disturbance factor of the rock mass (D).
Conditions of failure graphs for profile 6a showed that at low D (less than 0.4), earthquake forces and
watertable elevation must be unrealistically high for the region (greater than 0.33 g; greater than 15% watertable
elevation) in order produce a factor of safety less than 1. The remaining five slope profiles showed
potential to be unstable under realistic earthquake forces and watertable elevations. Two of these
profiles were unable to achieve stability at D greater than 0.8 (profile 4) and D greater than 0.9 (profile 5). A D value
of 0.6 (intermediate between 0.4 and 0.8) is argued to most realistically represent Putauaki. The
fact that Putauaki has not undergone large scale failure to date supports the conclusion that the
constructed models overestimate the influence of those factors which promote slope instability.
Maximum and minimum landslide run-out zones were constructed for the slope profiles exhibiting
the potential for large scale failure. Definition of the position and extent of maximum and
minimum run-out zones assumed H/L (fall height to run-out length) ratios of 0.09 and 0.18
respectively, as well as the 'credible flow path' concept. Identified impacts of landslides sourced
from Putauaki include inundation of Kawerau Township, Tarawera River, forestry operations, road
networks, and power supplies. Based on these impacts, the risk posed by landslides from each
slope profile was categorised as ranging from relatively low to relatively high. Landslides sourced from the south-west flanks pose a relatively low risk due to their prerequisite of unrealistically
high watertable elevations and earthquake forces. Landslides sourced from the north-west flanks pose a relatively high risk as minimum run-out will inundate north-east parts of Kawerau
Township. Landslides sourced from the eastern flanks pose a moderate risk due to their run-out
zones avoiding Kawerau Township.

year: 2007

title: The experience of homemaking in unaffordable and precarious housing

authors: Barrett, Patrick

abstract: Housing is the platform on which people build their lives. The experience of homemaking in unaffordable and precarious housing (Barrett, P., Cram, F. & James, B, 2024) is a new monograph from the Affordable Housing for Generations programme. Across 110 pages, 10 housing researchers share experiences from different groups of people in Aotearoa, burdened by the insecurity of unaffordable housing. The findings show how institutional, social and market dynamics impacting on life circumstances can cause people to be in precarious housing situations. Yet people continue to love homemaking and being contributors to their communities. Reinforcing the pivotal nature of housing in supporting all peoples’ health and wellbeing, this research demonstrates how much more can be achieved through improving access to stable, affordable housing and by understanding what is at the heart of a home.

text: The experience of homemaking in unaffordable and precarious housing Housing is the platform on which people build their lives. The experience of homemaking in unaffordable and precarious housing (Barrett, P., Cram, F. & James, B, 2024) is a new monograph from the Affordable Housing for Generations programme. Across 110 pages, 10 housing researchers share experiences from different groups of people in Aotearoa, burdened by the insecurity of unaffordable housing. The findings show how institutional, social and market dynamics impacting on life circumstances can cause people to be in precarious housing situations. Yet people continue to love homemaking and being contributors to their communities. Reinforcing the pivotal nature of housing in supporting all peoples’ health and wellbeing, this research demonstrates how much more can be achieved through improving access to stable, affordable housing and by understanding what is at the heart of a home.

year: 2024