Drought Status

  • Current status: Guarded
  • Action: Voluntary reductions in water usage.

Water Advisory Levels

  • Normal Precautions Action: Voluntary reductions in water usage.
  • Guarded Action: Voluntary reductions in water usage.
  • Warning Action: Voluntary reductions in water usage with some mandatory requirements.
  • Emergency Action: voluntary reductions in water usage plus additional mandatory requirements.
  • Shelter Island Disaster Action: All of the above action plus additional actions as required by the County or State.

Drought Indication Criteria

The Drought Indicator Criteria consists of three components, and/or requirements resulting from a New York State proclamation of Drought Emergency or Disaster.

Criteria #1 - U.S. Seasonal Drought Outlook

This is a forecast from the National Integrated Drought Information System (NIDIS), providing a map of the forecast drought tendency for the next 3 months. The site is at The drought tendency used in the determination of Shelter Island water restriction regulation is: Drought persists.

Criteria #2 - Drought Severity Monitor Report

This is a measurement from the Northeast Regional Climate Center (NRCC) of the current intensity of drought conditions. The intensity scoring is calculated by the NIDIS from ground moisture levels, water storage reserves, and long and short-term precipitation records. The Intensity Levels used in the determination of Shelter Island water restriction regulation are D3 Severe Drought or D4 Exceptional Drought.

Criteria #3 - Shelter Island Well Height Levels

'Normal' drought measurements rate the current water quantity versus the total capacity of a system. For example, the total capacity of a reservoir versus the amount measured within it. For Shelter Island groundwater quantity, because of the uncertain and varying saltwater diffusion zone, the "capacity" of potable water in the aquifer is difficult, perhaps impossible, to determine. For this reason, the monthly readings for monitored wells are compared to the seasonal historic well levels to provide relative guidance on available water.

The Shelter Island criteria is based on the % rank of the most current months well height readings compared to that month's historic median values for 4 of the wells that are evaluated by the USGS. These wells are the highest water-level test wells on the island. They are generally in the interior regions of the island aquifer and represent the "push" of fresh potable water out to the perimeter to keep salt water from intruding into the shore area wells, in effect the pressure tank for the aquifer. These wells are:

Big 4 Wells:

  • Manhasset Well #1
  • Manwaring Road Well #4
  • Congdon Road Well #5
  • Shelter Island Heights (Goat Hill) Well #12

The Shelter Island Indicator Well Height Level Drought Criteria: Percentile rank of 4 Indicator wells.

  • Average > 20% Normal Precautions
  • Average 20% to 15% Guarded
  • Average 15% to 10 % Warning
  • Average 10% to 5% Emergency
  • Average < 5 % Disaster

Criteria #4 - New York State Drought Proclamation

The State of New York has a separate grading system for drought awareness and regulation. The Governor/State DEC can announce levels of drought based on many of the criteria above. The proclamation of a Water Emergency stage or Disaster appears to result in state-mandated water conservation actions.

  • Watch - No impact on SI ranking
  • Warning- No impact on SI ranking
  • Emergency - 3 Stages: State 1,2 or 3- Mandatory defined by NY State
  • Disaster Proclamation - Follow Mandatory defined by NY State