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Enforcement Branch |
Enforcement Letter 2001-017, Attachment 1
MOLINATE WATER MANAGEMENT REQUIREMENTS--2001
I. All water from fields treated with products containing molinate must
be retained on the site of application for at least 28 days following
application unless:
A. The water is contained within a tailwater recovery system, ponded
on fallow land, or contained in other systems appropriate for
preventing discharge. The system may discharge 29 days following
the last application of molinate within the system.
1. If the system is under the control of one permittee, water
may be discharged from the application site in a manner
consistent with product labeling.
2. If the system includes drainage from more than permittee,
water may be discharged from the application site into the
system nine days following application.
B. The water is on acreage within the bounds of areas that discharge
negligible amounts of rice field drainage into perennial streams
until fields are drained for harvest. All water on fields treated
with molinate must be retained on the treated acreage until the
twelfth day following application.
C. The water is on acreage treated with a preflood application of
molinate. The label restrictions apply.
II. Fields not specified in I.A., I.B., and I.C. may resume discharging field
water 29 days following application at a volume not to exceed two inches
of water over a drain box weir. Unregulated discharges from these fields
may then resume after seven days.
III. The county agricultural commissioner may authorize the emergency release
of tailwater 12 days following the last molinate application, following a
review of a written request (Form A), which clearly demonstrates the crop,
is suffering because of the water management requirements. All water
management requirements must be followed that are associated with other
pesticides that my have been applied to the site. Additionally, the
requester must describe preventative action that would avoid the need for
future emergency releases. Under an emergency release variance, tailwater
may be released only to the extent necessary to mitigate the documented
problem. Those issued an emergency release must submit to the county
agricultural commissioner a report (Form B) indicating the time and
duration of the emergency release and data that can be used to calculate
the total amount ofwater release during the emergency release. Emergency
release will only be granted for reasons related to rainfall, high winds,
or other extreme weather conditions that cannot be moderated with management
practices.
IV. The county agricultural commissioner may authorize the emergency release
of field water on the 12th day following the last molinate application,
following the review of a written application that demonstrates salinity
levels are damaging to the crop.
A. Applicants for such emergency releases must provide the following
information:
1. All information indicated on the emergency release request form
(Form A), including a description of the severity and extent of
salinity damage.
2. Electrical conductivity (EC) measurements, expressed as
deciSiemans perimeter (dS/m) or microSiemans per centimeter
(µS/cm), from field water in each paddy suspected of having
salinity problems. To most effectively demonstrate salinity
problems, measurements should be taken wherever salinity
problems are evident.
3. The instrument (make and model) used to determine EC
measurements. The instrument must have a sensitivity range that
accommodates the full range of EC values in intake and paddy
water (usually a range of 0-5.0 dS/m or 0-5,000 µS/cm should
be sufficient) and should have a resolution of not less than
five percent. The instrument must be calibrated according to
the manufacturer’s instructions. The applicant must specify
the method of temperature compensation (i.e., automatic,
conversion table).
4. Who made the EC measurements.
5. The source of irrigation water (e.g. district supply canal,
drainage canal, well etc.).
B. An emergency release may be granted only if all of the following
conditions are satisfied.
1. All required information is provided.
2. Water management requirements for rice pesticides other than
molinate are satisfied.
3. EC of paddy water exceeds 2.0 dS/m or 2,000 µS/cm.
4. The county agricultural commissioner or his or her staff
inspects the site.
C. Water may be released from paddies where EC measurements exceed 2.0
dS/m or 2,000 µS/cm and from paddies downgradient from such paddies
within the same field. Water shall only be released in an amount
necessary to mitigate the salinity problem.
D. Those issued an emergency release must submit to the county agricultural
commissioner a report (Form B) indicating the time and duration of the
emergency release and data that can be used to calculate the total amount
of water released during the emergency release.
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