Question

Create an evaluation rubric to use to review the potential landslide risk in San Bernardino County, California. Follow the guidelines below. Your group is asked to create an evaluation rubric to identify factors that will influence the potential for damage from future landslides. This community is in a region where urban development has expanded right up to the foothills of the mountains. Consider the physical factors that contributed to the significant debris flows in Venezuela as you fill in the table to identify high-risk versus moderate-risk versus low-risk conditions. One factor, thickness of regolith, is completed in the table as an example. List as many additional factors as you can.

Short answer

Create a rubric considering slope, rainfall, soil, vegetation, and human activity, tailored to San Bernardino's characteristics.

Step-by-step solution

Understanding Landslide Risk

Before creating an evaluation rubric, it is crucial to understand the factors contributing to landslide risks. These factors include natural elements such as rainfall, slope angle, vegetation cover, soil and rock type, and human activities like urban development. San Bernardino's proximity to the mountains further requires attention to historical landslide occurrences in the area.

Listing Potential Risk Factors

Identify and list factors that influence landslide potential. Examples include: 1. **Slope Angle**: Steeper slopes have a higher risk. 2. **Rainfall**: Heavier and more frequent rain increases risk. 3. **Soil Composition**: Loose, granular soil types like sand increase risk. 4. **Vegetation Cover**: Sparse vegetation can destabilize the ground. 5. **Human Activities**: Construction can weaken slopes by altering natural drainage.

Categorizing Risk Levels

Classify each factor into high-risk, moderate-risk, and low-risk categories: - **Slope Angle**: High-risk at >30°, moderate-risk at 15-30°, low-risk at <15°. - **Rainfall**: High-risk with >2000 mm/year, moderate-risk with 1000-2000 mm/year, low-risk with <1000 mm/year. - **Soil Composition**: High-risk with predominance of loose granular soil, moderate-risk with mixed soil types, and low-risk with cohesive soils like clay. - **Vegetation Cover**: High-risk if less than 25% coverage, moderate-risk if 25-50%, low-risk if more than 50%. - **Human Activities**: High-risk in areas with recent heavy construction, moderate-risk in areas with minor developments, low-risk in undisturbed areas.

Design the Rubric Table

Create a rubric table with columns for factors, high-risk conditions, moderate-risk conditions, and low-risk conditions. Use the classifications from Step 3 to fill in the table. For example: | Factor | High-Risk Condition | Moderate-Risk Condition | Low-Risk Condition | |------------------------|-------------------------------|------------------------------|-----------------------------| | Slope Angle | >30° | 15-30° | <15° | | Rainfall | >2000 mm/year | 1000-2000 mm/year | <1000 mm/year | | Soil Composition | Loose granular | Mixed soil types | Cohesive clay | | Vegetation Cover | <25% coverage | 25-50% coverage | >50% coverage | | Human Activities | Recent heavy construction | Minor developments | Undisturbed areas |

Consider Regional Specifics

Adjust the rubric to consider specific characteristics of San Bernardino, such as historical landslide data and specific vegetation types. Include community feedback in high-risk areas for a comprehensive assessment.

Key concepts

Evaluation Rubric

An evaluation rubric serves as a detailed framework used to assess the potential landslide risk in a region like San Bernardino County. A well-constructed rubric helps in identifying the key factors that influence risk levels, allowing local authorities to make informed decisions and implement safety measures effectively. In developing this rubric, start by clearly defining the criteria to be evaluated, such as geographical, meteorological, and human-influenced elements.

• Criteria Definitions: State what each factor means. For example, how do you measure or define slope angle or vegetation cover?
• Risk Levels: Define what constitutes high, moderate, or low risk for each factor.
• Scoring/Weighting: Assign scores or weightings to different factors, indicating their importance relative to overall risk.

Creating a rubric involves understanding the local context, so factors particularly relevant to San Bernardino County, such as historical landslide data and community infrastructure, should be taken into account. The rubric provides a structured approach to systematically evaluate landslide risks, ensuring comprehensiveness and consistency in the assessment process.

Landslide Factors

Landslide factors are the various conditions and elements contributing to the likelihood of a landslide occurring. In San Bernardino County, understanding these factors is key to assessing risk accurately. Here are some crucial landslide factors:

• Geological Factors: Slope angle, soil composition, and rock type play significant roles. Steeper slopes and loose, granular soil types often increase landslide risks.
• Meteorological Factors: Rainfall patterns greatly impact landslide probability. Areas that experience frequent, heavy rainfall are particularly vulnerable.
• Biological Factors: Vegetation cover affects soil stability. Dense root systems help hold soil in place, reducing landslide risk.
• Human Factors: Activities like construction and urban development alter natural drainage patterns and slope stability, elevating landslide risk.

By thoroughly analyzing these factors and their interactions, you can better predict the situations under which landslides are more likely to occur and thereby mitigate their impact on the community.

Risk Categorization

Risk categorization is the process of classifying landslide risks into high, moderate, and low categories. This is essential for prioritizing mitigation efforts and resource allocation. Each risk factor is analyzed to determine its potential impact under various conditions:

• High Risk: Conditions that significantly exacerbate landslide potential, such as steep slopes over 30°, annual rainfall exceeding 2000 mm, and areas with recent heavy construction.
• Moderate Risk: Less severe conditions like slopes between 15° and 30°, rainfall between 1000 mm and 2000 mm annually, and areas with minor developmental activities.
• Low Risk: Areas with flatter terrains (slopes under 15°), rainfall less than 1000 mm yearly, cohesive soils like clay, and undisturbed regions.

The process of categorizing risk helps in identifying regions that need more immediate attention and resources for landslide prevention measures. This systematic approach ensures that high-risk areas are prioritized and more effectively managed.

San Bernardino County

San Bernardino County, located in California, has unique characteristics that influence landslide risk assessment. The county's proximity to mountain ranges, coupled with an expanding urban population, makes it particularly vulnerable to landslides. Historically, the region has experienced significant landslide events, particularly during heavy rainfall seasons.

• Geography: The county's varying elevations and mountainous terrain increase the likelihood of landslides.
• Climate: Seasonal rainfalls can be intense, elevating landslide risks during certain periods.
• Urban Development: Rapid expansion into hillside areas has changed natural drainage systems, impacting slope stability.
• Historical Context: Previous landslide events provide data crucial for predicting future occurrences and preparing communities accordingly.

It's essential that landslide risk assessments in San Bernardino take these regional specifics into account, incorporating feedback from the community for a comprehensive approach to risk management and disaster mitigation.