Page MAC Pt. 6, R. 9.5
LAYOUT OF THE TABLES
Cite as Page Miss. Admin. Code Pt. 6, R. 9.5
LAYOUT OF THE TABLES
A. Stream Listings
The impaired waters in Tables 3-5 below are sorted alphabetically by the river basin then by the
water body name. The extent of the segment is described beginning with the upstream boundary
thence to the downstream boundary. The maps of these segments are located in Appendix A.
B. Pollutants Included
The pollutants are
listed specifically for
each listing. There
are 239 listings for
2026.
Biological
Impairment is listed
223 times (93.3%).
This
listing
is
generated based on
assessing the result
of
our
benthic
sampling
program
M-BISQ. When the
water body is scored
below
the
eco-
regional value, it is
added to the impaired
waters list. A stressor identification process is then used to identify the specific pollutants causing
the microbiological impairment. Organic Enrichment, Total Nitrogen, and Total Phosphorus
listings are for excessive nutrients or organics which impact the dissolved oxygen and
eutrophication in the water body. The pH listings are from water monitoring results which are
outside of the water quality criteria for pH. If there are multiple pollutants and/or uses for a water
body, these are shown as multiple listings for the water body.
C. Pollutant Source
Due to the nature of the monitoring and listings for 2026, the source of the impairment is generally
not known. For the biological listings a stressor identification process is required to identify
probable primary stressors. Once identified, these probable primary stressors are incorporated into
the ยง303(d) List and the biological impairment listing is removed.
D. Water Body Identification Numbers
MDEQ and USGS completed work on the new 12-digit watershed-based delineation of Mississippi
in 2005. MDEQ incorporated this new delineation into the identification numbering system for
water body segments in the states beginning with the 2006 ยง305(b) report. Each listed water body
segment is identified by a six-digit numeric code. The first digit identifies which basin contains
the water body. The major river basins are numbered 1 through 9 in alphabetical order (1 for the
Big Black River Basin, 2 for the Coastal Streams Basin, through 9 for the Yazoo Basin.) [See map
on page 4.] The next three digits in the six-digit water body identification number refer to the
specific subwatershed within that basin. Each major river basin has the subwatersheds it contains
numbered beginning with 1 (subwatershed 146 located in the Big Black River Basin would be
numbered 1146, subwatershed 74 located in the Pascagoula River Basin would be numbered
4074.) The final two digits in the six-digit water body identification number refer to a specific
stream segment within the specified subwatershed. For instance, Beaver Creek, water body ID
521413, is stream segment 13 in subwatershed 214 in the Pearl River Basin.
E. Basin Maps
Maps are included in Appendix A for each basin. Streams shown in blue are the impaired stream
segments. In some river basins, the maps were split into 8-digit Hydrologic Unit Codes to better
fit the page.