Risk management and land use planning for environmental and asset protection purposes

The PhD thesis presents a semi-quantitative methodology, developed to increase the efficacy of Land Use Planning related to the Management of risks, in particular as far as it concerns multiple risks impinging on the same territory (Multi-risks). At the moment, each risk is managed through a dedicated sectorial plan, having its proper procedures and scale, and the only “meeting point” for these plans – at least in Italy - are the Municipal city plans. The Municipalities have to implement the contents related to the various risks and directly intervene on the territory, but the lack of linkage and coordination between the plans and the authorities in charge often makes the emergency management and LUP less effective towards the achievement of a real safety of territories. In addition, the actual legislative framework does not face the possible consequences of risk interactions. In this context, the objective of the thesis was to develop a simple risk pre-screening tool, expressly designed for local planners, able to point out the areas more exposed to risks and risks interactions, in order to better address the distribution of the municipal resources for further studies and interventions. The local planners that, especially in Italy, have a central role for the risk management of the territory, became the central point for the proposed framework, assuming the role of evaluators, and then decision-makers. The methodology was developed taking into account the existing experimental frameworks developed for Multi-risks and NaTech events. Both qualitative and quantitative methodologies were settled in the last years, however the scales and the complex approaches proposed collide with the objectives of this PhD thesis. In fact, few methodologies were elaborated for little scales, and frequently the application of quantitative multi-risk methodologies at a local scale encountered difficulties related to data availability; in addition, all the methodologies require the involvement of experts of several disciplines. These aspects, in particular considering the scarce financial resources of Municipalities, risk to limit the awareness of the importance of a multi-risk approach for LUP planners. Therefore, a semi-quantitative approach, based on an index scale from 0 to 3 onwards was developed for a direct use from Municipal technicians; the proposed scale is applied to measure both the impact of the risks and risk interaction. The methodology is composed by 4 steps: 1) characterization of the risks; 2) assignation of the ratings to the risks; 3) assessment of binary risk interactions; 4) assessment of the compatibility and planning phase. Each step is accompanied by GIS mapping. Steps 1 and 2) Risk characterization and rating. The users (local planners) are required to describe the main territorial risks according to 3 macro-categories: Historical Events, Protection Measures and Strengthening Effects. The macro-categories help in majorly focus on the different aspects of the risks, in particular those that could enhance its final impact, or that could have been neglected in the existing plans. Each macro-category is evaluated and rated on the basis of a dedicated guide, developed on the basis of literature data. Step 3) Risk interaction. The impact of one risk on another one (binary interaction) is assessed in the areas where risks overlay, thanks to a weighted average sum of the values of their macro-categories. An excel table for the application of the formula was developed. The calculation of the interaction vales can be also executed directly through GIS. Step 4) Compatibility. Territorial and environmental vulnerabilities are classified in compliance with E.R.I.R. national and regional regulations. Then, the compatibility is assessed on the basis of an “alarm threshold”; when highly vulnerable territorial or environmental elements fall down in areas where the risks macro-categories or risks interaction are above 2,5, a potential incompatibility is detected. The Municipalities will have to focus here further studies, and then possible interventions: a collection of the possible actions, extracted from existing Guidelines and Manuals was drafted to guide this process. An optional step for the compatibility assessment was added to provide the Municipalities with an indicative mapping of the spatial consequences of the interactions involving industrial plants. This is the only step of the methodology that could presents difficulties for not expert users, because it entails the use of two modelling software (ALOHA and HSSM), that simulates the consequences of the releases. The methodology was tested on two Italian case-studies, two Municipalities affected by multiple types of risks which could interact. Both the territories were connoted by low levels of risk, however the application of the methodology highlighted possible unforeseen problems deriving from the interactions, that currently are not described in any existing sectorial or local plan. Once that the areas more exposed are identified, ad-hoc investigations and actions can be settled to address the problem, on the basis of a guide-line. The proposed approach demonstrated to be able in identifying and bring multi-risks aspects to the attention of the decision makers; in this way, they have a simple guide to risk that can be integrated with the existing planning instruments to improve the quality of decisions related to risks. Furthermore, local administrators recover a more active role, increasing their awareness about the contents and information of the sectorial plans, but also exploiting their major direct knowledge of the territory. This approach tried to fill two different existing gaps: on one side, the absence of an official and recognized legislation on Multi-risks; on the other side, the difficulties for non-risk experts to effectively use the Multi-risk and NaTech experimental methodologies developed so far now. The framework developed for this PhD thesis can be easily adapted to LUP procedures of other countries, through a re-construction of the tables that guide the risk-rating; the simple index scale can be easily managed by different types of users. Being the methodology a risk pre-screening, it can be useful in every context in which it is necessary to acquire more information about multi-risks and their consequences, to better define future actions and drive the application of quantitative methodologies.