The Preliminary Planning component of the Clean Water Plan advises ALCOSAN on the size, location and route of new conveyance tunnels, dropshafts, regulators, and shallow conveyance sewers that will be constructed.  It will also integrate data from our treatment plant expansion and GROW programs to determine the need and best uses of the proposed facilities.


Preliminary Planning Activities

The Preliminary Planning process will include the following activities and culminate in the issuance of a Basis of Design Report. 

  • Establishing tunnel lengths, alignment, and sizing refinements 
  • Evaluation of wet weather pump station alternatives 
  • Geotechnical investigations and assessments 
  • Property evaluation and assessment 
  • Tunnel system hydraulics and surge analysis 
  • Flow management and operational strategies 
  • Evaluation of construction packaging and project delivery alternatives

Current Status

The following plan and evaluation activities are underway:

  • Geotechnical data collection – Boring into key locations to study the soil and rock characteristics
  • Source controls, green infrastructure, flow optimization
  • Operational strategies, grit management, optimization
  • Alternatives evaluation

The anticipated next steps for Preliminary Planning include:

  • Continue planning and evaluation tasks
  • Continue to coordinate with the treatment plant expansion and GROW efforts
  • Incorporate municipal plans for source controls as they are provided
  • Update draft facility plan 
  • Draft basis of design report 

Quick Links

Stormwater protection with native plants and gravel
ALCOSAN’s GROW Program Announcement

Grants available up to $10 million per project.

See Press Release for Details
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