Herdendorf, Charles E.

KnowledgeBank at OSU

STATE OF OHIO DEPARTMENT OF NATURAL RESOURCES DIVISION OF GEOLOGICAL SURVEY Horace R. Coll ins, Chief Report of Investigations No. 7 4 WATER MASSES AND THEIR MOVEMENTS IN WESTERN LAKE ERIE by Charles E. Herdendorf Columbus 1969 STATE OF OHIO DEPARTMENT OF NATURAL RESOURCES DIVISION OF GEOLOGICAL SURVEY Horace R. Col I ins, Chief Report of Investigations No. 7 4 WATER MASSES AND THEIR MOVEMENTS IN WESTERN LAKE ERIE by Charles E. Herdendorf Columbus 1969 GEOLOGY SERVES OHIO ~ CONTENTS Introduction ............................ . ........ ...... .. ... . . . . ...................... .. .. . Water masses and movements . . ............................... . . .. . . .. . ... . .. . ...... . Velocities of water masses . ....... .... . . . ... ....... . ........................ .. ...... . Summary ............................. .. .................................................... . References cited ...................... . ...... . ..... . . . ... .. . ... .... . ............. ... . . . . ILLUSTRATIONS Figures 1. Water temperatures at 10-foot depths in western Lake Erie on June 23, Page 1 3 3 7 7 1963; sampling stations shown by dots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Surface conductivity of western Lake Erie on June 23 , 1963 . . .. . .. .. . .. 4 3. Water level fluctuations in western Lake Erie as recorded at U.S. Army Corps of Engineers gauge in Toledo , Ohio , on June 17 through 23, 1963. Low water levels indicated by letters A, B, C, and D correspond with water masses A, B, C, and D ....... . .. 5 4. Temperature and conductivity profiles near the mouth of the Detroit River on June 18, 1965 .. .. .. .. . . . ... . .... .. . . . . .. . . . . . . . . . . . . . . . ....... ... 6 111     Blank Page WATER MASSES AND THEIR MOVEMENTS IN WESTERN LAKE ERi E INTRODUCTION A synoptic survey of several of the physical and chemical characteristics of the water in western Lake Erie was conducted on June 23 , 1963 , by the Ohio De-partment of Natural Resources. The main objective of the study was to determine the feasibility and value of a synoptic survey of water properties as a method of mapping water masses and of determining their origins and paths of movement. Western Lake Erie was se-lected as the area in which to conduct the survey for several reasons. West of the island chain between Marblehead and Pelee Point the lake forms a natural basin. This basin is the recipient of large influxes of water, each with its distinctive properties, from the Detroit and Maumee Rivers and from the central basin of Lake Erie. The area of western Lake Erie is also relatively small , slightly less than 1,300 square miles , making it possible to survey the entire basin within a single day. These features made this basin an ideal area in which to conduct a water property study. The Ohio Division of Wildlife contributed three boats for the survey: Explorer, lnv es ti gator, and In-spector. The Ohio Division of Geological Survey pro-vided its research vessel , GS-1. Sampling stations were established on a two-mile grid, resulting in a total of 300 stations (fig. 1). Stations were allotted to each vessel in a pattern such that all sampling could be accomplished within a period of eighteen hours. At each station water samples were taken with Kemmerer water samplers at two depths: five feet be-low the surface and two feet above the bottom. At the time of sampling, water temperatures were measured 1 by Charles E. Herdendorf to the nearest degree Fahrenheit. The samples were analyzed within three days of the survey for the fol-lowing properties: (1) turbidity, (2) hydrogen-ion con-centration (pH), and (3) specific conductance. Tur-bidity values were obtained with a Hellige turbidi-meter. Hydrogen-ion concentrations were determined with a Beckman Zeromatic pH meter. Specific con-ductance (conductivity) was measured with an Indus-trial Instruments conductivity meter, model RC 16B2 , and reduced to micromhos per cm at 25°C. Conductivity yields a measure of the capacity of water to convey an electric current. This property is related to the total concentration of ionized substances in the water and to water temperature. In general, the ratio of total dissolved solids to specific conductance for western Lake Erie is 0.59. In addition to these measurements, bathythermograph temperature recordings were made on a four-mile grid and were reported by Herdendorf (1967) . Dissolved oxygen and alkalinity determinations were made at the time of sampling for those samples taken from the Explorer and were discussed in a report by Carr, Applegate, and Keller (1965). Water color observations were recorded from the GS-1. The results of the field measurements and labo-ratory analyses were plotted on charts of western Lake Erie , using U.S. Lake Survey Chart 39 as a base. The values for each property were contoured in order to establish areal patterns of circulation, if such existed. Preliminary results of this investigation were re-ported by Hartley, Herdendorf, and Keller (1966a, b). They concluded that conductivity and water tempera-tures below the zone of diurnal heating were the most reliable indicators of water masses . An attempt was also made to interpret the movement of these masses. s3•30• s3 °20• s3 °00• s2°50' s2°40• ONTARIO Pigeon Bay rt' ~,0 '*0 41 ·1 50' 10---:--·1 •I . • I . ,..,. ii~·;-·:" -~:- ·-· • I Fl • ......_ ./ ~ 0: I I I ... I 40' :i>1. II '>,., 10· ( J ~ I INSPECTOR I I I ,Kelleys Is. . ~ .... SCALE OF MILES --- ------10 5 0 ~.?~- I ·I I I~~· Sampling location Temperature (°F at 10-foot depth, contour interval 1°) FIGURE 1.-Water temperatures at 10-foot depths in western Lake Erie on June 23, 1963; sampling stations shown by dots . ~ l I. N ~ > >-l tI1 :;d 3::: > [./) [./) tI1 [./) ...... z ~ tI1 [./) >-l tI1 :;d z r-' > :;.:: tI1 tI1 :;d ...... tI1 MOVEMENTS AND VELOCITIES 3 The following report is presented as a supplement to the earlier interpretations: movements of water masses in western Lake Erie are further discussed and a method for computing movement velocities is devel-oped. WATER MASSES AND MOVEMENTS The water property survey of June 23, 1963, dem-onstrated that water masses can be mapped, particu-larly those created by major inflows . Emphasis must be placed on the fact that the following interpretations are based on the results of a one-day survey conducted in early summer during a period of calm weather when disturbing influences were at a minimum. It is likely that strong winds and pronounced seiche activity can significantly disrupt the pattern described in this re-port. Subsurface temperatures obtained from bathythermo-graph recordings at the 10-foot depth , when plotted and contoured , showed a definite southward movement of relatively cold midchannel Detroit River water flanked by warmer water on both sides. The contours in figure 1 suggest that this warmer water was moving southwest-ward along the Michigan shoreline and eastward along the Ontario shoreline. The midchannel flow split about 10 miles south of the river mouth, with the bulk of the flow continuing in a southerly direction and a lesser branch moving eastward toward Pelee Passage. Tem-perature values also indicated an eastward movement of water along the Ohio shore from Maumee Bay and a northward flow of warm water west of the Bass Islands as well as an insurgence of cooler central Lake Erie water in the southern island area and in Pelee Pas-sage. Surface conductivity values showed definite pat-terns which appeared to be related to individual water masses (fig. 2). The water with the highest conduc-tivity was found west of the Detroit River mouth and appeared to have been moving southward. The patterns indicate that this flow may have joined another water mass which also had high conductivity and had been moving southeastward from the Maumee River along and near the Ohio shore. Another mass of water with high conductivity was noted on the west side of the Bass Islands, but water with low conductivity was found in the southern island area and south of Pelee Point . This suggests that water from along the Ohio shore west of Catawba was moving northward on the west side of the islands, and that the southern island area and , to a lesser extent, Pelee Passage were re-ceiving an influx of central Lake Erie water. A band of water with relatively low conductivity extended southward from the midchannel of the Detroit River to the Ohio shore near Locust Point. This flow appeared to bifurcate about 10 miles southeast of the river mouth, with a substantial flow moving eastward along the Ontario shoreline to Pigeon Bay, thence southeastward toward Pelee Passage. The midchannel flow from the mouth of the Detroit River to the Ohio shore was characterized by four podlike masses of water with very low conductivity. These pods are labeled A through D on figure 2 and are of consider-able importance in computing the velocity of this flow. VELOCITIES OF WATER MASSES Lake level fluctuations in western Lake Erie for six days preceding the survey are shown in figure 3. On each of the four days immediately before the sur-vey , seiche activity caused the lake level to fall and rise noticeably. The low points of these fluctuations are labeled A through D on figure 3. This suggests that these times of low lake levels are related to the four pods of water with very low conductivity which are shown in figure 2. During the four low lake levels a larger volume of midchannel Detroit River water ap-parently entered the lake because of the increased sur-face gradient. The succeeding higher levels decreased the hydrostatic head and thereby lessened the rate of flow. The conductivity patterns reflect this phenome-non by showing a pod with low conductivity for each period of low lake level, the pods being separated by water with medium conductivity. The matching of the four pods with the four periods of major low levels that preceded the survey appears to be justified because low water l~vel B of June 20, 1963, is the lowest lake level recorded in the six days prior to the survey and low conductivity water mass B contains water with the lowest conductivity readings. Presumably the size of the pod is dependent upon the relative lowness of the lake level and the amount of dispersion which occurred after the mass entered the lake. Once a pod has been correlated with its corre-sponding period of low lake level, its average velocity can easily be computed by dividing the distance it has traveled by the time that has elapsed since the related low level. The following table shows the relative movements of these pods: Position of Distance between pods pods (mi) D to C C to B B to A 12 8 4 Time between Velocity low levels (hrs) mph fr/ sec 24 28 14 0.50 0.74 0.29 0.43 0.29 0.43 ,l:>. 83°30' 82 ° 50' _ ........ ~ I .. ~~'.'.~~d······· 4 2" I I " I ::;J)/t}.l:::::::::::: ::r:x:-:o.~:·.•:·~· I""' I .....  ... ;.·.·;·:·:·.~· ·· ·1 ··· · oo. I , _..._""" .· ,,,,,,,,,,::,,:::::s;.:,fr:,,,,,,, .. '" 41 ° 50' . - ··················-------------- ----- -- -- -· - --- ------------------------ · 41 • 1 ~ 50 ' > ..., trl :::d a: > (/) (/) trl (/) ...... z ~ trl (/) ·-·-·- I ..., trl 41 ° :::d 40' z l' I ~m···--···~~8r·"~·====== r= ======= = ====· I I I > SCALE OF MILES ::-:: -- I I '/t:: ·::·:·:::::~f' .... . .~! ' diHi ~~~ytl)/KlWl~ifl trl 10 51 ,0 I trl :::d ...... trl ., I I "'"1····~ : ~ ~ : ~:::::::::::.6 ) l l A::-~~ii/~i~t;~~11> I I I ~ more than 275 micromhos/ cm 1:::::::::1 250 to 275 micromhos/ cm 41 · 1~ 200 to 250 micromhos/ cm 30' ~ less than 200 micromhos/ cm I I ~...> I I ~I~ .,., I ~ I I I 41 ° 30' 83 ° 30" 83 °20 ' 83 ° 10' 82 °50' 82 °40' 82 °30' FIGURE 2.-Surface conductivity of western Lake Erie on June 23, 1963 . .... ----... June 22 June 23 study period FIGURE 3.-Water level fluctuations in west.em Lake Erie as recorded at U.S. Army Corps of Engineers gauge in Toledo , Ohio, on June 17 through 23 , 1963. Low water levels indicated by letters A, B, C. and D correspond with water masses A, B, C, and D. a;:: 0 < t'rJ a;:: t'rJ z .-.j (/) > z t:l < t'rJ r-' 0 n ::i ~ (/) V\ 0 5 Qi 10 <1> .._ c £ 15 c. <1> 0 ~ I 20 25 30 Maple Beach, Mich. (west) Bar Point, Ont. (east) 0 5 6'v. .... 10 <1> ~ c SCALE OF MILES .s:: Cl. 15 <1> 0 - -- - -0 3 2 4 5 20 - Conductivity (micromhos/ cm at 25 °C) 25 - - Temperature (°F) 30 Stony Point, Mich. (west) Colchester 0 ' nt. (east) \ I I l I \ I \: 0 " <O \ I I cfl I 'j: I ')' I I I I I g & I I 0 \ 0 ~ 0 "' 0 I "' N - <O N 0 \.11 <O <O <O "' \ \ \~~// \ \ \ ~ t / \ I . /T ,' \ O> ">s J I I O> ~ ~ ,' \fld ~ ,~ 0 <O I \ I I I \ \ \ \ I I I ' \ I I \ FIGURE 4 .-Temperature and conductivity profiles near the mouth of the Detroit River on June 18, 1965. °' ~ > >-l trl ~ :::: > (/) (/) trl (/) z ~ trl (/) >-l trl ~ z I:""' > ~ trl trl ~ ...... trl SUMMARY 7 The average velocity computed for water moving from the position of pod D to the position of pod A was found to be 0.36 mph or 0 .53 ft/sec. This indicates that Detroit River water normally would reach the Ohio shore llO hours, or approximately 4Yi days , after it entered the lake at the river mouth. The computed velocities of these pods are gener-ally substantiated by direct measurements. Currents were measured with an Ekman meter at a station mid-way between Middle Sister and West Sister Islands on July 1 and July 8, 1964, for a total of ll hours. These currents were found to be moving southerly at all depths . Velocities near the surface ranged from 0.2 to 0.5 ft/ sec . Data collected from this station show the same directions as those interpreted from the tempera-ture and conductivity patterns and the calculated ve-locitie s also agree reasonably well with the measured values. Temperature and conductivity surveys near the mouth of the Detroit River on June 18, 1965 , showed distinct water masses consistent with those found on June 23, 1963. Two profiles were made of Detroit River water, one at the river mouth along a line between Maple Beach, Michigan , and Bar Point, Ontario, and another about seven miles to the south in western Lake Erie between Stony Point , Michigan , and Colchester , Ontario. Temperature and conductivity were measured at five-foot depth intervals from s urface to bottom: at quarter-mile intervals at the river mouth and at mile intervals in the lake. The river profile shows three distinct water masses (fig. 4). Water with higher tem-perature and greater conductivity occupied the shal-lower areas along the east and west shores ; the mid-channel flow was cooler and lower in conductivity . The lake profile indicates that five zones or water masses were present south of the river mouth: it appears that midchannel flow divided upon entering the lake and was separated by western basin water with higher con-ductivity. This profile correlates with the surface con-ductivity pattern of the June 23, 1963, study (fig. 2), which shows a split in the midchannel flow about 10 miles southeast of the river mouth , producing southerly and easterly flows. SUMMARY The synoptic water property study has demon-strated that a sampling and analysis program carried out in a sh ort time and in a dense pattern can be valu-able in determining the existence, shapes, movements, and velocities of water masses. Temperature and conductivity values indicate a dominating southward movement of the Detroit River water, some of which reached the Ohio shore near Locust Point . Part of the midchannel main flow ap-pears to split off and move eastward near the Ontario shore. Water along the sides of the Detroit River has higher temperature and conductivity values and pro-duces sluggish flow that generally clings to the shore-line or forms eddy currents . Measurements indicate an eastward movement of water along the Ohio shore from Maumee Bay to the Bass Island area and thence north-ward along the west side of the islands. A northwest-ward flow of central Lake Erie water into the southern islands area and south of Pelee Point is also recog-nized. Most of the flow from western Lake Erie into the central basin appears to be through Pelee Passage. Variations in water levels, when correlated with podlike masses of water which have entered the lake from the Detroit River, provide data for determining the velocity of their movements. The average velocity of Detroit River water flow in western Lake Erie is approximately 0.5 ft/ sec. REFERENCES CITED Carr, J . F., Applegate, V. C. , and Keller, M., 1965, A recent occurrence of thermal s tratification and low dissolved oxygen in western Lake Erie: Ohio Jour. Sci. , v. 65 , p. 319-327. Hartley, R. P. , Herdendorf , C. E., and Keller, M., 1966a, Synoptic survey of water properties in the western basin of Lake Erie: Ohio Geol. Survey Rept. Inv . 58, 19 p. ____ 1966b, Synoptic water sampling survey in the western basin of Lake Erie , 9th Conference Great Lakes Research Proc.: Michigan Univ., Great Lakes Research Div. Pub. 15 , p. 301-322. Herdendorf, C. E., 1967, Lake Erie bathythermograph recordings, 195 2-1966: Ohio Geol. Survey Inf. Circ. 34, 36 p. 

Water masses and their movements in western Lake Erie

https://kb.osu.edu/bitstream/1811/80320/1/OGS_1969_RI-74.pdf

Water masses and their movements in western Lake Erie

Abstract

Similar works

Full text

Available Versions

KnowledgeBank at OSU