FLOOD_RISK_ASSESSMENT_V2-1335967.pdf

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FLOOD_RISK_ASSESSMENT_V2-1335967

Summary

Key Points:

  • The site is within Flood Zone 1, indicating low flood risk.
  • Surface water runoff and drainage are critical considerations.
  • Recommendations for detailed drainage plans and site-specific infiltration tests.

Summary:

The flood risk assessment indicates low overall flood risk but emphasises the importance of managing surface water runoff through comprehensive drainage solutions.

Weak Points:

1. Scope of the Flood Risk Assessment

  • Insufficient Coverage: The current assessment may not fully address the broader hydrological impacts on lower-lying areas such as Beechlands Road and Red Hill, and Lymington Bottom.
  • Lack of Cumulative Impact Analysis: The study may not adequately consider the cumulative impact of both the existing and proposed developments on downstream locations.

2. Historical Context and Previous Developments

  • Lack of Full Environmental Impact Assessment (EIA): Previous developments in the rural area did not undergo a comprehensive EIA, leading to unaddressed flood risks and environmental impacts.
  • Omissions in Historical Data Review: The assessment may not thoroughly incorporate historical flood data and local knowledge, which are crucial for understanding the current flood risks.

3. Detailed Drainage Plans and Testing

  • Lack of Detailed Drainage Plans and Infiltration Tests: The absence of detailed drainage plans and infiltration tests at this stage could delay the project if required later.

4. Effectiveness of Drainage Solutions

  • Ensuring Effective Drainage Solutions: The effectiveness of the proposed drainage solutions in preventing any increase in flood risk to surrounding areas must be ensured.

5. Existing Flooding Issues

  • Exacerbation of Existing Flooding Issues: The development may exacerbate existing flooding issues at the Beechlands Road and Red Hill junction, potentially making the situation worse for residents.
  • Previous Mitigation Efforts: The Beechlands Road and Red Hill junction, which is lower than the already delivered estate and the proposed one, often floods. Previous road fixes by the developer have not resolved the issue.

What aspects should be evaluated in relation to this document?

Specific Considerations

Topographical Analysis:

  • Assess how the topography influences water flow from the development sites to lower-lying areas, particularly during heavy rainfall events.
  • Ensure that the flood risk assessment considers the cumulative impact of both the existing and proposed developments on the wider area, including downstream locations.

Hydraulic Modeling:

  • Use hydraulic modeling to simulate how water flows through the entire catchment area, taking into account the topography and existing drainage infrastructure.

Monitoring and Feedback:

  • Implement monitoring systems to track the effectiveness of mitigation measures and adjust them as necessary based on observed impacts.

Historical Flood Data:

  • Review historical flood data for Beechlands Road, Red Hill, and Lymington Bottom to identify patterns and potential triggers related to the development.

ENVIRONMENTAL IMPACT

Sustainable Drainage Systems (SuDS):

  • Evaluate the design and effectiveness of SuDS proposed for managing surface water on the site. Ensure they provide adequate storage and infiltration for storm events, including allowances for climate change.
  • Assess the long-term maintenance plans for SuDS to ensure continued effectiveness in managing flood risks.

Flood Risk Assessment:

  • Review the methodology and conclusions of the flood risk assessment to ensure it adequately considers the site’s risk from tidal, fluvial, groundwater, and overland flow flooding.
  • Confirm that the development will not increase flood risk elsewhere, particularly in lower-lying areas such as the junction of Beechlands Road and Red Hill, and Lymington Bottom in Medstead.

Stakeholder Involvement:

  • Evaluate the extent of community engagement in the planning process. Ensure that local knowledge and concerns about flood risk have been addressed.
  • Assess the impact on lower-lying areas, such as the junction of Beechlands Road and Red Hill, and Lymington Bottom in Medstead, which may be affected by increased runoff from the development.

INFRASTRUCTURE AND SERVICES

Drainage Systems:

  • Assess the adequacy of the proposed surface water and foul drainage systems. Ensure they can handle peak flows and have appropriate maintenance plans.
  • Evaluate the potential cumulative impact of the drainage systems from both the existing and proposed developments on the wider area’s drainage network.

Water Quality:

  • Evaluate measures for protecting water quality, particularly regarding surface runoff and foul water discharge.

LOCAL AND NATIONAL PLANNING POLICIES

Compliance with NPPF:

  • Verify that the development complies with the National Planning Policy Framework (NPPF) guidelines for flood risk management.
  • Ensure the development meets criteria for flood resistance, resilience, and safe access/escape routes.

Local Planning Policies:

  • Review alignment with local policies from East Hampshire District Council and Partnership for Urban South Hampshire (PUSH).
  • Ensure adherence to site-specific flood risk policies and strategic flood risk assessments.

RESIDENTIAL AMENITY

Safety and Accessibility:

  • Assess the safety measures in place for future residents, particularly regarding flood risk and emergency access routes.
  • Evaluate the impact of flood risk management on the overall quality of life for residents.

DESIGN AND APPEARANCE

Integration with Surrounding Environment:

  • Ensure the development’s design integrates well with the surrounding environment and does not negatively impact the visual landscape.
  • Assess the aesthetic and functional design of flood management infrastructure within the site.

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