An Act Regarding Riverine Impoundments
Maine Legislature, Session 121, LD 1137
Committee: Natural Resources
Sponsors: PINEAU, WOODCOCK, CLARK, JENNINGS, PATRICK, SA VIELLO, BLAIS, DAVIS, STANLEY
Amends: 38 MRSA §464, 38 MRSA §465-D, 38 MRSA §466, 38 MRSA §467

Legislative Document 
No. 1137 
H.P.840 
House of Representatives, March 4,2003 
An Act Regarding Riverine Impoundments 
Reference to the Committee on Natural Resources suggested and ordered printed. 
Presented by Representative PINEAU of Jay. 
Cosponsored by Senator WOODCOCK of Franklin and 
7J1~/J7.~ 
MILLICENT M. MacFARLAND 
Clerk 
Representati ves: CARR of Lincoln, CLARK of Millinocket, JENNINGS of Leeds, PATRICK 
of Rumford, SA VIELLO of Wilton, Senators: BLAIS of Kennebec, DAVIS of Piscataquis, 
STANLEY of Penobscot. 
Printed on n:cycled paper 
Be it enacted by the People of the State of Maine as follows: 
Sec. 1. 38 MRSA §464, sub-§4, 1(J is enacted to read: 
J. 
Licensed discharges existing on or after the effective 
date of this paragraph that do not increase the phosphorus 
concentration in the receiving water body more than one part 
per 
billion 
are 
considered 
de 
m~n~m~s 
and 
any 
such 
discharges are not considered to be causing or contributing 
to any water guality impairment or to a 
failure of the 
receiving 
water 
body 
to 
meet 
the 
standards 
of 
classification. 
If 
a 
water 
guality-based 
effluent 
limitation for phosphorus is necessary, the department shall 
allow, 
at a 
m~n~mum, a 
monthly average mass 
loading in 
pounds per day of total phosphorus egual to a one part per 
billion increase in the receiving water body. 
The monthly 
average mass loading must be calculated using a phosphorus 
concentration of one part per billion at the 7-day low flow 
that can be expected to occur with a freguency of once in 10 
years at the point of discharge. 
Sec. 2. 38 MRSA §465-D is enacted to read: 
§465-D. 
Standards for classification of riverine impoundments 
The 
department 
shall 
have 
one 
standard 
for 
the 
classification of riverine impoundments that thermally stratify. 
Impoundments of rivers that are defined as great ponds pursuant 
to section 480-6 and are classified as GPA under section 467 
remain subject to the standards in section 465-A. 
1. 
Class RI waters. 
Class RI is the sole classification of 
riverine impoundments that thermally stratify. 
A. 
Class 
RI 
waters are of such guality that they are 
suitable for the designated uses of drinking water supply 
after treatment; fishing; recreation in and on the water; 
industrial process and cooling water supply; hydroelectric 
power 
generation 
except 
as 
prohibited 
under 
Title 
12, 
section 403; 
and navigation; and as habitat for fish and 
other aguatic life. 
6. 
Discharges to Class RI waters may cause some changes to 
aguatic life, 
as 
long 
as 
the 
receiving waters 
are 
of 
sufficient guality to support a1l applicable life stages of 
species of fish that are indigenous to the receiving waters 
and maintain the structure and function of the resident 
biological community. 
In determining whether water is of 
sufficient guality to support indigenous fish, water guality 
must support fish populations in those seasons, and in those 
• 
• 
specific 
habitats 
within 
the 
impoundment, 
needed 
for 
passage, spawning, egg incubation and survival of early life 
stages. 
In determining whether water guality is sufficient 
to support other aguatic life, the department shall consider 
the effects of 
thermal 
stratification to 
be 
a 
natural 
condition and those waters may not be considered to be 
failing their classification. 
C. 
Between May 
15th and September 30th, 
the 
number of 
Escherichia coli bacteria of human origin in these waters 
may not exceed a geometric mean of 142 per 100 milliliters 
or an instantaneous level of 949 per 100 milliliters. 
Sec. 3. 38 MRS A §466, sub-§8, as enac ted by PL 1985, c . 698, 
§15, is repealed and the following enacted in its place; 
8. 
Indigenous. 
"Indigenous" 
means 
historically 
or 
currently present naturally in the State's waters without having 
been brought directly or indirectly to the State's waters. 
Sec. 4. 38 MRSA §466, sub-§10-A is enacted to read: 
lO-A. 
Thermal 
stratification. 
"Thermal 
stratification" 
means a change in temperature of at least one degree Celsius per 
meter of depth, causing waters below this temperature gradient to 
remain isolated and not to mix with waters above the temperature 
gradient. 
Sec. 5. 38 MRSA §467, sub-§l, ,A, as affected by PL 1989, c. 
890, Pt. A, §40 and amended by Pt. B, §68, is further amended to 
read: 
A. 
Androscoggin 
River, 
main 
stem, 
including 
all 
impoundments. 
(1) 
From 
the 
Maine-New 
Hampshire 
boundary 
to its 
confluence with the Ellis River - Class B. 
(2) 
From its confluence with the Ellis River to a-Jiae 
Ee~mea-~-~~~~~&&iG&-ef-~~~~~~*-BeQaaa~y 
ae~ess-~~~~-~-ia-~-~~~~~~-ai~ee~ieB 
Turner Bridge in Turner - Class C. 
(3) 
From the Turner Bridge in Turner to Gulf Island 
Pond Dam - Class RI. 
(4) 
From Gulf Island Pond Dam to a line formed by the 
extension 
of 
the 
Bath-Brunswick 
boundary 
across 
Merrymeeting Bay in a northwesterly direction 
Class C. 
Sec. 6. 38 MRSA §467, sub-§4, ,H, as repealed and replaced by 
PL 1989, c. 228, §2, is amended to read: 
H. 
Sebasticook River Drainage. 
(1 ) 
Sebasticook 
River, 
main 
stem, 
including 
all 
impoundments. 
(a) 
From the confluence of the East Branch and 
the 
West 
Branch 
to 
its 
confluence 
with 
~Re 
KeBBeaee-RiveF Burnham Pond - Class C. 
(b) 
From its confluence with Burnham Pond to the 
Burnham Pond Dam - Class RI. 
(c) 
From the Burnham Pond Dam to its confluence 
with the Fort Halifax impoundment - Class C. 
(d) 
From its confluence with the Fort Halifax 
impoundment to the Fort Halifax Dam - Class RI. 
(e) 
From the Fort Halifax Dam to its confluence 
with the Kennebec River - Class C. 
(2) 
Sebasticook River, tributaries 
otherwise specified. 
Class B unless 
(a) 
Sebasticook River, 
East Branch main 
from 
the 
outlet 
of 
Lake 
Wassookeag 
to 
confluence with Corundel Lake - Class B. 
stem, 
its 
(b) 
Sebasticook River, 
East Branch main 
stem, 
from the outlet of Corundel Lake to its confluence 
with the West Branch - Class C. 
(c) 
Sebasticook River, 
West 
Branch main stem, 
from 
the 
outlet 
of 
Great 
Moose 
Lake 
to 
its 
confluence with the East Branch, 
including all 
impoundments - Class C. 
Sec. 7. 38 MRSA §467, sub-§7, ,C, as amended by PL 1999, c . 
277, §10, is further amended to read: 
C. 
Penobscot River, West Branch Drainage. 
(1) 
West Branch of the Penobscot River, main stem. 
(a) 
From the dam at the outlet of Seboomook Lake 
to a point located 1,000 feet downstream from the 
dam at the outlet of Seboomook Lake - Class B. 
• 
.. 
• 
(b) 
From a point located 1,000 feet downstream 
from the dam at the outlet of Seboomook Lake to 
its confluence with Chesuncook Lake - Class A. 
(b-l) 
From its confluence with Chesuncook Lake to 
Ripogenus Dam -
Class GPA as modified by section 
464, subsection 9. 
(c) 
From Ripogenus Dam through Ripogenus Gorge to 
the McKay powerhouse - Class B. 
(d) 
From the McKay powerhouse to its confluence 
with Ambajejus Lake - Class A. 
(e) 
From the outlet of Elbow Lake to the outlet 
of Ferguson and Quakish Lakes - Class B. 
(f) 
From the outlet of Ferguson and Quakish Lakes 
to its confluence with 
~ae--&a&~-~~-~--~ae 
PeBeesee~-~-r-iBe~~eiB~-~~--impeQBQmeB~s QQ1Qy 
Pond - Class C. 
(g) 
From its confluence with Dolby Pond to the 
Dolby Pond Dam - Class RI. 
(h) 
From Dolby Pond Dam to its confluence with 
the East Branch of the Penobscot River, including 
all impoundments - Class C. 
(2) 
West Branch of the Penobscot River, tributaries -
Class A unless otherwise specified. 
(a) 
Those 
segments of 
any tributary that are 
within the boundaries of Baxter State Park - Class 
AA. 
(b) 
Those tributaries above the confluence with 
the Debsconeag Deadwater, any portion of which is 
located within the boundaries of Baxter State Park 
- Class AA. 
(c) 
Millinocket Stream, from the railroad bridge 
near the Millinocket-T. 3 Indian Purchase boundary 
to its confluence with the West Branch Canal 
Class B. 
(d) 
Millinocket Stream from the confluence of the 
West Branch Canal to its confluence with the West 
Branch of the Penobscot River - Class C. 
SUMMARY 
This 
bill 
creates 
a 
new 
classification 
for 
riverine 
impoundments that thermally stratify during some portion of the 
year. 
Currently, these waters are classified as Class C water 
bodies, and are limited to 4 impoundments: 
Gulf I sland Pond, 
Dolby Pond, Burnham Pond and the Fort Halifax impoundment. 
The 
bill does not apply to impoundments classified as GPA. 
Historically, impoundments were classified as either Class C 
or 
Class 
GPA 
depending 
upon 
the presence of upstream point 
sources. 
Impoundments 
downstream 
from 
point 
sources 
were 
classified as riverine waters, 
for example, 
Class 
C, 
because 
discharges were prohibited to GPA waters. 
A riverine designation, however, does not accurately reflect 
the physical 
characteristics of 
some 
of 
these 
impoundments. 
Unlike free-flowing rivers, 
some riverine impoundments exhibit 
important 
lake-like 
characteristics, 
such 
as 
thermal 
stratification. 
The 
RI 
Class 
provides 
appropriate 
criteria 
reflective of these physical characteristics while, at the same 
time, ensuring maintenance of existing water quality. 
For 
purposes 
of 
determining 
whether 
water 
quality 
is 
sufficient to support habitat for fish and aquatic life, water 
quality is to be measured when existing fish populations are 
present and at locations in the water body necessary to support 
all life stages of existing fish populations. 
In determining 
whether the water is of a quality to support other aquatic life, 
effects 
associated 
with 
thermal 
stratification, 
including 
inhibited mixing, are considered natural conditions. 
This 
bill 
establishes 
a 
de 
minimis 
level 
for 
total 
phosphorus discharges. 
The de minimis level is based on the 
minimum 
detectable 
total 
phosphorus 
concentration 
using 
low 
detection limit analyses and clean sampling techniques. 
This bill repeals and replaces the existing definition of 
"indigenous" 
by 
specifying 
that 
introduced 
species 
are 
not 
indigenous to waters of the State. 
A new definition of thermal 
stratification has been added. 
• 
..