Public Law-84-99

Public Law 84-99


PL-84-99: The U.S. Army Corps of Engineers provides emergency assistance to state and local governments before, during, and after flood events under Public Law 84-99. Funded through the Flood Control and Coastal Emergencies appropriation, our services include technical expertise and direct support for flooding, coastal storms, hurricanes, and earthquake-related flood risks. Assistance is available upon state request and supplements existing local resources and National Guard capabilities.


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TOP NEWS
Press Release for Old Sacramento Flood Wall Dye Test here

PL-84-99 Overview

Public Law (PL) 84-99 Fact Sheet for Flood Response

PURPOSE:

This fact sheet explains flood-response assistance that can be provided from the U.S. Army Corps of Engineers under Public Law 84-99 and the correct process that must be followed to request assistance.

BACKGROUND:

USACE emergency assistance under PL 84-99 during flood events will be of a temporary nature to meet the immediate threat and will be undertaken only to supplement State and Local efforts. State, tribal, and local interests must commit all available resources, i.e. work force, supplies, equipment, funds, National Guard assets, etc., as a general condition of USACE assistance. USACE emergency efforts are not intended to provide permanent solutions to flood problems and are provided strictly for the protection of public facilities and infrastructure.

PL 84-99 TECHNICAL ASSISTANCE

This authority is initiated during a flood event and rivers are either forecast, at, or above flood stage. Emergency Operations technical assistance consists of providing review and recommendations in support of State and Local efforts, and helping determine feasible solutions to uncommon situations.

  • - Guidance on flood fight techniques and emergency construction methods from experienced personnel 
  • - Provide experienced personnel to inspect existing flood protection projects to identify problem areas and recommend corrective measures 
  • - Provide hydraulic or hydrologic analysis, geotechnical evaluations, and stream data, maps, and historic flood or storm information

USACE is authorized to provide more in-depth technical assistance to communities threatened with imminent flooding potential under the Advance Measures program. Unlike Emergency Operations technical assistance, Advance Measures technical assistance must be requested in writing by the State Emergency Management Agency or Tribal Official, and requires HQUSACE approval.

  • - Evaluate flood threat to area 
  •  - Supplement data collection efforts 
  •  - Inspect existing Flood Control Works and identify problems 
  •  - Provide engineering technical services 
  •  - Provide information for local contingency/flood fight plans

PL 84-99 DIRECT ASSISTANCE:

This authority is initiated during a flood event, when river are forecast, at, or above flood stage as predicted by the National Weather Service. Emergency Operations direct assistance may include:

- Assisting with flood fight efforts 

- Conducting field investigations/data collection 

- Providing emergency flood fight supplies 

- Initiating emergency contracting for construction of protective measures (e.g. temporary levees)

Requirements for Direct Assistance:

- Supplemental to state/tribal/local government flood fight efforts 

 - Impacts to urban areas or critical public infrastructure only . Temporary in nature and directed to the immediate threat 

 - Request from local/counties must be made to the State Emergency Management Office for their review and processing 

 - USACE must receive request from the State/Tribe to provide assistance 

 - Request must include a detailed assessment of the resources committed, the current actions of the locals/County/State/Tribe, what type of assistance is requested, point of contact and specific details on exactly what the community is looking for in assistance. 

 - Loaned supplies and equipment (pumps, sandbags, and innovative flood barriers) must be returned in the same condition as it was when lent, replaced in kind, or reimbursement made to USACE 

 - Project economically feasible, reasonable, prudent and constructible before flood 

 - Project Cooperation Agreement required 

 - Applicants/Locals are physically and fiscally responsible for removal of all temporary flood protection features at the end of the event 

 - Applicants must furnish all borrow, lands, rights, easements, and rights-of-way 

 - Applicants must make necessary relocations - Hold harmless the U.S. Federal Government free from damages 

 - Applicants must provide traffic control during construction 

 - Applicants must provide monitoring for levees and pumping operations

USACE is also authorized to provide supplemental direct assistance prior to the event for communities threatened with imminent flooding potential under the Advance Measures program. In addition to the requirements stated above, the following are also required:

  • - If a State is requesting assistance, the written request must be signed by the Governor.   
  • - A Project Information Report must be prepared by the local USACE district, and approved by HQUSACE   
  • - A benefit-cost ratio greater than 1.0 must exist

 

Site 0441-04 Old Sacramento

 

Site 0441-04- Old Sacramento Floodwall Investigation & Design Planning  | Project Duration: 2025-2028

What's Happening

The U.S. Army Corps of Engineers Sacramento District will conduct dye testing of the Old Sacramento floodwall along the Sacramento River beginning Mid October 2025, as part of a comprehensive project to investigate and monitor soil and water flow that was observed after flooding in 2023.

 

Current Status: The floodwall remains safe and operational while investigations proceed.


Key Project Details


Current Phase: Investigation and Design Planning
Dye Testing Period: Mid October - December 15, 2025 
Expected Green Water: Residents and boaters will see bright green river water during testing


Investigation Process


Fluorescent Dye Testing

Engineers will use green fluorescent water tracing dye to assess water movement between the Sacramento River and soil behind the floodwall which will identify the most comprehensive repairs.


Additional Testing Methods

  • Soil sampling and testing on both sides of the floodwall
  • Soil displacement measurements 
  • Water level monitoring in river and soil conditions
  • Underwater camera monitoring of dye dispersion
  • Specialized detection equipment for precise measurement

Safety Information


The Green Dye is Completely Safe

  • Food-grade and non-toxic
  • Biodegradable and non-staining
  • Safe for people, fish, wildlife, and vegetation
  • Washes out easily from surfaces and fabrics
  • Only small amounts used compared to river volume

Detection Timeline: Depending on conditions, the dye may be visible from seconds to weeks.

Program Authority


This project operates under Public Law 84-99, which authorizes the Army Corps of Engineers to assist communities with flood preparedness and response, including rehabilitation of levees and floodwalls.


Project Partners


Coordinating Agencies:

  • U.S. Army Corps of Engineers Sacramento District
  • City of Sacramento
  • California Central Valley Flood Protection Board

 

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