Michigan Department of Natural Resources
Genesee & Lapeer counties (T8N, R8, 9E, Section Many)
William C. Bryant
Holloway Reservoir is a 1,973 acre impoundment on the Flint River (Figure
1). It is located in eastern Genesee and western Lapeer counties. Most
of the reservoir is encompassed by the Holloway Reservoir Regional Park.
Mott Reservoir, a smaller impoundment, is located about 5 miles downstream.
Because of its size and proximity to Flint, Holloway Reservoir provides
a major aquatic resource for this otherwise relatively lakeless area of
The upper Flint River watershed contains a wide mixture of soils (24
main soil types have been identified) of glacial drift origin. The watershed
contains 1,400 square miles, and is part of the Saginaw River drainage
basin. The river drains 95% of Genesee County, 80% of Lapeer County, and
10% of Shiawassee County. The Holloway Reservoir shoreline varies greatly
from marshy edge to gently sloping open shoreline to steep sand bank shoreline.
The Flint River is designated as a top quality, warmwater stream, but
three smaller tributaries are presently being managed for trout.
The City of Flint began construction of Holloway Reservoir in 1951. Full
operation of the dam began in 1955. The original uses of the Reservoir
were potable water supply and flow augmentation. Recreation, in addition
to flow augmentation, became emphasized when the City began to obtain
its potable drinking water from Lake Huron in 1967.
Flint River water is of the calcium bicarbonate type and is very hard.
Hardness has been recorded in the range of 240 to 300 ppm (Ellis Arndt,
and Truesdell, Inc. 1972). Agricultural nonpoint sources (NPS) are a major
contributor to the overall pollutant level in the Flint River. McColley
and Karkowski (1982) reported that one year's loadings of phosphorus in
the Flint River from NPS equalled that of 14 years of wastewater treatment
Fisheries Division's management of the Holloway Reservoir fishery resources
has been vigorously pursued since early in its existence. The first netting
survey, conducted in 1969, revealed that a warmwater fish population,
rather typical of eutrophic southern Michigan waters, was already well
established. Black crappies were, by far, the most abundant species collected.
Carp, the second most abundant species, contributed to the significant
turbidity. Dense summer phytoplankton blooms, another cause of turbidity,
developed relatively early in the reservoir's existence.
The first attempt to alter the resident fish stocks in Holloway Reservoir
occurred in 1961 with the introduction of fingerling muskellunge. This
stocking effort was unsuccessful; no muskies were ever taken in nets or
reported caught by anglers. The reservoir and it's upstream watershed
were treated with rotenone in the fall of 1971 in an attempt to totally
eradicate the fish population. Later that fall, and in 1972 and 1973,
the reservoir was stocked with large numbers of young largemouth bass,
northern pike, bluegill, channel catfish, and walleye. Additionally, rainbow
trout were introduced those same years to produce an interim fishery.
A netting survey in 1972 revealed that carp, in particular, had not been
eradicated by the treatment. Instead, survival of young carp was evidently
greatly increased, as often follows attempts to artificially lower carp
abundance. In 1976, Holloway Reservoir was again treated with rotenone
to suppress the carp population in the headwaters and upper impoundment.
Substantial numbers of fingerlings, and in some cases adults, of 10 sport
fish species were stocked after the treatment.
A 1978 survey determined that carp were again abundant. Black crappies
of acceptable size to anglers were exceptionally numerous. Young-of-the
year walleye were collected during a 1980 electrofishing survey which
suggested that significant natural reproduction of this species was occurring.
Surveys in 1983 and 1984 revealed that bluegills were abundant and growing
well. Black crappies were also abundant, but were growing somewhat slowly.
Walleyes were growing exceptionally well and were providing a summer fishery.
Despite heavy stockings in 1976 and 1977, only one tiger muskie was collected.
These results, plus earlier (1961 and 1962) stockings and a lack of angler
success, combine to indicate very poor survival of this species in this
The most recent trap-netting survey was in 1989. The results, summarized
in Table 1, confirmed the findings of earlier surveys showing reservoir
fish population dominated by black crappies and carp. Gizzard shad are
not listed in Table 1, but they have gained access to the lake, from unknown
sources in recent years, and are now an additional dominant species. Age
analyses presented in Tables 2 and 3 clearly indicate that growth of fishes
most important to the fishery-e.g., bluegill, yellow perch, black crappie,
and walleye was quite satisfactory (well above state averages). Channel
catfish apparently grow very well. A cursory age analysis was made of
several 1990 angler-caught catfish from the Flint River below the Holloway
Dam. The mean length of seven age-VI catfish was 19.5 inches, and 11 age-VII
catfish averaged 22.9 inches long. This growth, if representative of the
reservoir population, would be exceptionally good. Most fish species of
angler importance in the Reservoir become more piscivorous with increasing
size. The expansion of the gizzard shad population, which at a small size
are ideal forage, has probably enhanced the growth of sport fish.
Holloway Reservoir is extremely fertile, and this is reflected in the
generally satisfactory growth and abundance of several fish species of
angler interest. The lake should be supporting a satisfactory sport fishery;
this needs to be confirmed by an on-site creel survey of angler effort
Two attempts to alter the fish community by rotenone treatment have not
eliminated carp. It is unclear whether the carp stock has been significantly
reduced. However, it appears that sport fish and rough fish are presently
coexisting at an acceptable level. Further attempts to reduce rough fish
density by conventional methods (rotenone treatment or manual removal
with nets) are probably not economically justified or realistically attainable.
The current stocking program for Holloway Reservoir calls for the planting
of walleye and tiger muskies every other year. There appears to be little
reason to continue to stock tiger muskies, since there has been a consistent
absence of reports of angler success. Conversely, walleye are providing
a fishery and they should continue to be stocked. Catfish appear to be
very common with obvious natural reproduction. They should require no
more than monitoring, and if necessary, harvest control measures can be
considered. As time allows, a study should be conducted to ascertain the
extent of natural reproduction of these two species. Walleyes, in particular,
may prove to be fully self-sustaining in the reservoir. White bass is
an additional species that might be considered for introduction. This
fertile impoundment offers a rich forage fish source that might prove
ideal for supporting this species. It would add further variety to the
fishery. A flourishing white bass population would, of course, introduce
a risk of interspecific competition. This competition might be fairly
small scale, but the potential risk should be thoroughly investigated
before introduction of the species.
The apparent greater abundance of smallmouth bass rather than largemouth
bass in the reservoir environment is puzzling and merits further study.
Although unproven at this time, it is quite possible that the highly organic
floc (from phytoplankton) settling out on the substrate causes difficulties
for nest-building species that spawn in the lower (deposition) area of
the reservoir. This floc material develops a strong septic odor, and it
is probable that at the substrate/water interface dissolved oxygen (DO)
becomes depleted, at times, during the warm months. This would occur most
frequently in protected shoal areas favored by nest builders. Thorough
testing of the DO near the substrate in late spring and early summer would
be useful in ascertaining the extent of this problem. Walleye, smallmouth
bass, and channel catfish are species that typically move into streams
to spawn and thus avoid potential low DO problems from this source.
The abandoned New York Central Railroad bridge, spanning the upper part
of the Reservoir in Columbiaville, prevents passage of all but very small
boats. Removal of the bridge would allow greater use of the upper end
of the impoundment by anglers, fisheries survey craft, and other watercraft.
Fisheries Division should pursue removal of this bridge.
This report has stressed that high fertility and turbidity are major
characteristics of this reservoir which must be considered in the management
of its fishery resources. This eutrophic condition has undoubtedly contributed
to the productivity of forage species and to valuable sport fish species
which prey upon them. The case for walleye, channel catfish, and their
prime forge, gizzard shad, has been made. This lake appears to have been
spared some of the damaging effects of eutrophication-e.g., excessive
weed growth and extensive DO depletion. I believe this is due primarily
to the shallowness of the basin coupled with water circulated from the
inflow of a fairly large stream (the Flint River). Limnological surveys
conducted four different summers revealed little to no thermal stratification.
DO measurements taken in 1968 and 1977 revealed adequate concentrations
for fish at all depths except for suspected depletion at the substrate
interface, as previously discussed. It is unlikely that thermal stratification,
with its potential for adverse biological effects, becomes well established.
Holloway Reservoir in its present condition is probably supporting about
as productive and valuable a sport fish population as can be reasonably
expected of it.
Each fall, the Holloway Reservoir's water level is dropped 4 feet to
prevent ice damage to, or deactivation of, the water control structures
for the dam. This drawdown normally begins about November 1 and restoration
to normal level is targeted to occur by May 1 (J. Weisenberger, City of
Flint Water Plant Supervisor). Effects of this mild drawdown on the fishery
resource have not been studied but most probably are minimal. Bennett
(1962), summarizing his Illinois work and many others' research findings,
conclusively demonstrated that wide annual fluctuations in lake levels
can have a pronounced favorable effect on game fish populations. This
applies to both natural and man-made lakes.
A permanent solution to lessening the overfertility caused by phosphorus
overloading, is long term, involving fundamental land use changes in the
watershed. A Flint River Basin management study prepared for Genesee,
Lapeer, and Shiawassee counties (GLS) concluded that improving water quality
ranks low within the agricultural community, because of high costs to
individual farmers in the face of depressed farm income (McColley and
Karkowski 1982). Funding for watershed improvement projects is a necessity,
but this has not occurred in the Holloway Reservoir watershed. The GLS
study recommendation for artificial bank stabilization in the Plum Creek
watershed upstream of the lake, has not occurred (J. Cousins, Lapeer County
Drain Commissioner, personal communication). A substantial drawdown of
the reservoir water level for a significant period of time is a potential
fishery management option to consider for the future, should the fishery
Report completed: January 13, 1992
Bennett, G. W. 1962. Management of artificial lakes and ponds. Reinhold
Publishing Corporation, New York.
Ellis, Arndt, and Truesdell, Inc. 1972. Master plan for the Holloway
Reservoir Regional Park. Ellis Arndt, and Truesdell, Inc., Flint, Michigan.
McColley, V. L. and R. J. Karkowski. 1982. Flint River basin management
study. Phase III-agricultural nonpoint sources. Genesee-Lapeer-Shiawassee
Region V Planning and Development Commission. Flint, Michigan.
Table 1.-Number, weight, and length (inches) of fish collected
from Holloway Reservoir with trap nets, July 16-18, 1989.
1Some weights were estimated from lengths.
Table 2.-Average total length (inches) at age, and growth relative
to the state average, for four fish sampled from Holloway Reservoir with
trap nets on May 16-18, 1989. Number of fish aged is given in parentheses.
1Mean growth index is the average deviation from the state
average length at age.
Table 3.-Estimated age frequency (percent) of four species of
fish caught from Holloway Reservoir with trap nets on May 16-18, 1989.
Last Update: 08/06/02