5. PREDICTING FLOOD HAZARD MITIGATION FEATURES AT THE
5.5 Summary and Conclusions
The conceptual model presented in Figure 3.1 provides a framework for
understanding the associations of planners’ commitments and role orientations with flood hazard mitigation features in development projects under their review. This chapter
presented regression results that test the statistical significance of hypothesized relationships between variables in the conceptual model. Overall, the data used for this study provide support for many but not all of the hypothesized relationships in the model. Figure 5.1
summarizes the results of the tests of hypotheses conducted in this chapter. Thick arrows indicate a positive association between variables; thin arrows indicate a negative association; dashed arrows indicate mixed associations.
Flood Hazard Mitigation • Land use locations
• Structural protection • Environmentally sensitive area protection Project Characteristics • Acres • Units • Location • Age • Exposure Community Characteristics • Flood history • Population • Population growth • Wealth Planner Characteristics • Commitment • Role orientations • Commitment*Role orientations • Capacity • Negotiation style
Site Plan Review Process • Public participation
• Development management
Figure 5.1 Revised Model of Factors that are Associated with Flood Hazard Mitigation Features
Several important themes emerge from the analyses presented in this chapter. First, as shown in Figure 5.1, variables from each dimension in the model (i.e. land use planner, site plan review process, community characteristics, and project characteristics) have a
significant association with flood hazard mitigation features. This finding helps justify the inclusion of each of these dimensions in the model, and corroborates the findings of previous researchers with respect to their importance for predicting natural hazard mitigation.
The second and most important theme is that planner characteristics relating to plan implementation are associated with flood hazard mitigation features, including the location of land uses relative to the floodplain and the protection of environmentally sensitive areas. These findings support (though do not prove) this study’s central thesis that planners can exercise discretion to promote particular causes during the process of plan implementation, and that the manner in which they do so helps determine the outcome of their efforts.
Whereas it is generally accepted in the plan implementation and natural hazard mitigation literatures that planners’ commitments can influence plan implementation (see Chapter 2), the findings in this study reveal limited associations between planners’
commitment to natural hazard mitigation and flood hazard mitigation features in particular development projects. Planners’ commitment to protecting public safety has no association with flood hazard mitigation, while planners’ commitment to environmental preservation is only associated with the location of infrastructure relative to the floodplain. However, the findings do give rise to the possibility that planners’ orientations may be an important factor in plan implementation. Significant associations are observed between three of the role orientations under study and flood hazard mitigation features, which may suggest that planners’ behaviors have implications for plan implementation. Certain behaviors (e.g. fostering public participation) are positively associated with flood hazard mitigation, while other behaviors (e.g. providing objective advice to decision-makers and/or openly promoting personal commitments) are negatively associated. Advising decision-makers is also
negatively associated with public participation, which raises the possibility that the Advisor role orientation has an indirect effect on the location of infrastructure relative to the
floodplain. Table 5.4 shows the Direct, and Indirect, and Total Effects for the Advisor role orientation and the Infrastructure variable. The direct effect is negative, the indirect effect is positive, and the total effect is negative. Together, these findings lend some degree of credence to the notion that the manner in which planners’ exercise their discretion has implications for planning outcomes beyond the nature and strength of planners’ commitments to particular substantive causes.
The third theme that emerges from the regression results centers on the influence of the site plan review process on flood hazard mitigation. First, public participation appears to have mixed associations with flood hazard mitigation features. The involvement of
environmental groups in site plan review is positively associated with locating infrastructure outside the floodplain and with preserving environmentally sensitive areas, while citizens raising issues with respect to natural hazards is negatively associated. Whereas the involvement of environmental groups can reasonably be expected to increase the odds of keeping floodplain areas free from infrastructure intrusion, the latter finding regarding citizens raising hazard-related issues is less reasonable. In reality, this finding is likely misleading in that citizens may have very well raised hazard-related issues because projects proposed to locate development (including infrastructure) inside the floodplain, rather than projects locating infrastructure inside the floodplain because citizens raised issues relating to natural hazards. The second aspect of the site plan review process, i.e. the strength of development management programs, is associated with locating residential land uses
features. It may be that communities are primarily concerned with protecting residential land uses from flooding, since the location of residential land uses relative to the floodplain is most directly related to the safety of human lives. To the extent that this is true, it is reasonable to conclude that development management programs may be more strongly associated with locating residential land uses outside the floodplain than with locating commercial and/or infrastructure outside the floodplain or protecting environmentally sensitive areas.
The final theme has to do with the associations between contextual variables and flood hazard mitigation. Findings for community flood history suggest that project design may depend in part upon characteristics of the community in which the project is located, while findings for project size, location, and floodplain exposure reveal the potential importance of site characteristics. Projects located in communities that had experienced recent flood disasters are found to be more likely to locate infrastructure outside the
floodplain, perhaps because participants in site plan review place a relatively high priority on hazard mitigation during such times. Table 5.4 shows that the direct effect of community flood history on the Infrastructure variable is positive, that the indirect effect is negative, and that the total effect is positive. Projects located on large parcels of land presumably have greater flexibility to avoid the floodplain, as projects with greater acreage are found more likely to locate residential land uses outside the floodplain. Acreage is also shown in Table 5.4 to have a positive indirect effect on locating infrastructure outside the floodplain.
Projects with large numbers of dwelling units have a harder time accommodating those units without encroaching upon the floodplain and other environmentally sensitive areas. Along these same lines, projects with large floodplain portions find floodplain avoidance more
difficult. Lastly, when projects locate in greenfield locations, they are more likely than infill/redevelopment projects to install new infrastructure (and thus more likely to locate infrastructure in the floodplain), and more likely to have environmentally sensitive areas in need of protection.
There are a few additional findings that warrant discussion. First, there are some variables that would appear to have indirect effects on flood hazard mitigation (based on the findings in Tables 5.2 and 5.3) but are found to have very small indirect effects that are essentially negligible. The first of these variables is median home value, which was found to be associated with the involvement of environmental groups and citizens raising hazard- related issues. However, the indirect effects of home value on the location of infrastructure relative to the floodplain mediated by the two public participation variables are shown in Table 5.4 to have odds-ratios very close to 1.00, suggesting that the effects are very small. The same is true for acreage, which was found in Table 5.3 to be associated with the
involvement of environmental groups, but is shown in Table 5.5 to have an indirect effect on the use of environmentally sensitive area protection techniques with an odds-ratio very close to 1.00.
The second set of additional findings that warrants discussion relates to the
development management program. As noted above in relation to Table 5.3, the regression model used to predict development management did not converge, and thus it is not possible to analyze direct and indirect predictors of development management. Given that
development management is found in Table 5.2 to be positively associated with locating residential land uses outside the floodplain, variables that help predict development
Variables that were expected to predict development management include community flood history, population, population growth, and median home values. Question marks in Table 5.4 for these variables in the Residential model reflect the inability in this study to examine the potential indirect effects of these variables on the location of residential land uses, mediated by their direct effect on development management.