:28 October 1970, Nearshore and Estuarine Zone Symposium, Portland, Oregon/by Alyn C. Duxbury. Duxbury, Alyn C.,1932- University of Washington.Dept. of Oceanography. University of Washington.Division of Marine Resources. Nearshore and Estuarine Zone Symposium(1970:Portland, Or.) Seattle, Wash.:University of Washington, Dept. of Oceanography:Division of Marine Resources,1970. Estuaries. Coast changes. Coastal Zone RLo-1725-184 Information .Conf-701064--1 Center GC UNIVERSITY OF WASHINGTON 97 DEPARTMENT OF OCEANOGRAPHY .D89 and 1970 DIVISION OF MARINE RESOURCES Seattle, Washington 98105 APR 18 1975 Jul 24 1997 Coastal Zone Processes and their Influence on Estuarian Conditions 28 October 1970 Nearshore and Estuarine Zone Symposium Portland, Oregon U.S. DEPARTMENT OF COMMERCE NOAA COASTAL SERVICES CENTER 2234 SOUTH HOBSON AVENUE by CHARLESTON, SC 29405-2413 Alyn C. Duxbury NOTICE This report was prepared as an account of work sponsored by the United States Government. Neither the United States nor the United States Atomic Energy Commission, nor any of their employees, nor any of their contractors, subcontractors, or their employees, nukes any warranty, express or implied. or assumes any legal liability or responsibility for the accuracy, com- pleteness or usefulness of any information, apparatus, product or process disclosed, or represents that its me would not infringe privately owned rights. Property of CSC Library Reference: M70:79 Oral Prescntation prepared under U.S. AEC Contract AT (45-1)-1725 and Grant GH-66 under the Sea Grant Program 25-184 r 1970 COASTAL ZONE GC INFORMATION CENTER 97 .D89 1970 DISTRIBUTION OF THIS DOCUMENT IS UNLIMITED COASTAL ZONE PROCESSES AND THEIR INFLUENCE ON ESTUARIAN. CONDITIONS Introduction A discussion of the estuarian and,coastal zone is norcomplete unless the'oceanic processes along the coast are also considered. On the basis of several premises, one can describe flushing rates or calculate the net circulation using salt and water budget equations in estuaries. However, estimates of this type are based on average conditions and thus are insen- sitive to the role that coastal waters may play in estuarian Circulation, especially when short lived density-driven displacement entersinto the problem. one can readily calculate the volume transport in along the bottom of the Straits of Juan de Fuca and the volume transport out at the surface that are required to =aintain the salt and water balance of the Straits of Georgia, Puget Souhd estuarine systems. These transports can be shown to very seasonally because of the changing freshwater discharge and the changing salinity of the Incoming ocean water and outgoing surface vater. The ability of the incoming water to flu.5'h the deep basins behind the shallow entrance sills Is not just a function of its supply and salt content, but also a function of its temperature, which combines with the salinity to control its density. Only when the incoming water at depth is supplied in sufficient quantity and density can it displace the deep basin water behind isolating sills in the estuarian environment. Thus, flushing of the deeper estuaries is not necessar- ily a continuous process, but can be periodic and is related to oceanic processes that combine to place a dense water in position where it can flow inward to the estuarian system. In the Strait of Juan de Fuca case, the dense water must be raised sufficiently in the water coll-n to clear the 180-m entrance sill of the Strait. COASTAL ZONE, INFORMATION -CENYE In other shallow coastal e.mbayments such as Willapa Bay and Cray's Harbor, there are no deep basins isolated by shallow entrance sills. Thus, flushing is more of a continuous process., However, even here the changing characteristics of the ocean water presented.to the bay entrance become important. The sudden appearance of a dense oceanic waterat levels shallow enough to enter the channels leading to these embayments can cause gravity flow into the bay that will bodily displace the water within the bay at a rate that is greater than @hat calculated from budget consider- ations. This type of flushing,,unrelated to that required for salt and water balance or tidal exchange, can be regarded as both good and bad. It, can be good if one considers-that it is a mechanism for rapidly reroving waste materials from-a semi-isolated embayment or bad if the flushing leads to the displacement of water that contains the planktonic stage of some desired benthic organism such as oyster larvae. The properties of the displacing water that make it dense, namely, high salinity and low temperature, may also create additional problems for biopop-, ulations in an embayment. The biopopulations adapted to a warmer,. less saline water may suffer considerably when a sudden flushing exposes them to a lower temperature-higher salinity water. The properties of the oceanic water and the.proce sses that act to present a variable type of oceanic water to the estuaries are part of near- coast.ocean environment. Thus, for a full understandiug of estuarian problems, we must also unaerstand the coastal regime. The Coastal Regime of Washington and qregon -Washington and Oregon is located at about the ..The coastal region of same Utitude as the center of the North Pacific West Wind Drift, the broad expanse of westward-moving water that is the northern side of the large North Pacific clockwise current gyre. This current often mistakenly referred to as the Japanese Currenti divides as it approaches the coast, sending one branch northward to feed the Guli of Alaska gyre and another branch south- ward to form a flow called the California Current. This latter flow, though not swift, is subtantial and enduring enough to'carry vister of the type found I-a the north central Pacific Ocean as far.south as the tip of Baja, California. The division of the West Wind Drift current into its two branches occurs about 11 x 102km, 600 a mi. off our coast. Thus, our Immediate coastal region appears to be well removed from the direct iniluence of this major oceanic surface current. Indeed,.our coastal region extending-out to about,5 x102km Is characterized by wealt and variable flows. Dynamic topographies that -he mean ocean surface current relative to the 1000 decibar level.in Z:he same way atmospheric pressure charts are used to deter- mine the wind fiv-.lt4 s%.vw'that surface currents are variable at about 5 cm/sec-1 off shore, abonc 2ilO of a knot, and about twice that, closer to shore. The low value of flow imposed by the oceanic scale currents in our coastal region allows the local processes.for generating cu rrents to become very important. Studies conducted in the coastal regions of Washington and Oregon point out that the local wind influence is instrumental in control- Ing the water circulation and that the seasonal.cycle in the prevailing wind system produces a seasonal cycle in-the coastwise flow and the properties of the seawater found'near shore. A reversal in the nearshore surface current during winter is evident. t During the s@-,nmer months, the North Pacific high pressure cell enlarg'es and migrates to a position where it, combined with the Canaiian Continental low cell pressure, produces predominately northerly winds of light magnitude. Duri ng the winLer the coudensing of the North Pacific high and the develop- ment of the Aleutian low cell cause south witids of stronger magnitude to predominate along the coast# This cyclic reversal in the local wind field is what causes the reversal in the alongshore'flow of the surface water. It also causes a reversal in the onshore and offshore component of the surface flow. During the winter, water from offshore is moved toward the coast and held locked in against the beach where it is mixed with fresh water issuing from the rivers and land drainage; and then it migrates northward. In the summer the surface water and river effluent are moved seaward from the coast and to the southwest. This onshore-offshore flow locally supplies seawater to the coast in the winter to cause downwelling and removes the surface seawater during th@-: summer necessitating upwelling of deeper water to maintain continuity. The movement of coastal water in response to the wind approximates that described in Ekman wind drift theory. That Is, the surface water moves stan angle of about 45 0 to the right of the wind stress vector while the transport of water as integrated,over the vertical column set in motion by 0 the wind is about 90 to the right of the wind. The transport and surface -ved. current as determined from Ekman theory closely agree with that obser Studies of the distribution of the Columbia River effluent under AEC support have shown that occasionally discrete cells of low salinity water are formed near the river mouth and migrate seaward as an identifiable mass of water. 'Their displacement over time nearly matches that predicted by Ekman drift in ..both speed and direction. The seasonal variation in the local surface currents greatly affects the type of water found adjacent to tLe coast where it exchanges with the estu- aries. In the summer the offshor-3 wind-induced transport causes coastal up- welling. Along the coast, this process brings water from depth up to the surface which has low temperatures zind high salinities. This upwelled water In response to the removal of surface water seaward forms a barrier of dense water that isolates the effluent from the Columbia River from direct contact with the coast. At this time of year the Columbia River becomes the major source of dilution for the region as freshwater contribution from smaller coastal rivers is at a minimum. The surface salinity patterns clearly reflect upwelling during summer and the importance of the Columbia River as a singular diluting scurce. In the winter the northward and onshore set of the surface flow under the driving wind stress produces another distribution of properties. The prevailing wind pattern at this time of year Is closely coupled with an appreciable increase in coastal precipitation. This increases the fresh- water discharge of all coastal rivers into the nearshore environment and makes the Columbia River less evident as a single source of dilution. One therefore sees a dilute band of seawater held In against the coast and tending northward. The surface salinity distributions during winter are ind1ca- tive of the flow. The surface wiuds are usually stronger in winter than in summer. Thus, even though the local currents tend to reverse seasonally, the north- ward flow in wint2r is greater than the southward flow in summer. This aide in producing a net trend of coastal water to the north over the annual cycle. Another process also acts to promote a norzhward-tending flow especially at depth. The presence of the Strait of Juan-de Fuca with its attached estuarian systems makes certain demands on the water at the coast. The water and salt budget equations show that an influx of bottom water Into the St raita of Georgia, Puget Sound System is on the a verage about 13 x 104m3see -1 with a range from 6 x 10 4m3sec-1 in winter to 26 x 104M3sec-1 In summer, This Is no small flow rate. At its mean value, it is more than 18 times the average annual discharge of the Columbia River. The outflow at the surface is equal to the inflow at depth plus the freshwater contribution. This influx at depth into the Straits and discharge at the surface acts to pull ocean water at depth alvag the coast toward the entrance enhancing a northward flow along the coast of Washington at'all seasons. The kind of water at depth to flow toward the Strait of Juan de Fuca is evident in the migration patterns of seabed drifters that have been released along the coast and picked up on the beaches or at sea by bottom trawlers. The Seasonal Change in Water Properties at the Coast. We should now consider the change in coastal water type that is associated with the &easonal wind reversal. To do this we will consider the characteristics of the water.in che Strait of Juan de Fuca. In midwinter, Febr@jary, data from i section across the Strait at Pillar Point show that at,50-m depth, water of 31.5 to 32 O/oo salinity increasing to 33.7 O/oo, at 180-m depth, and isothermal at SOC is avvilable as the incoming water to be mixed wkh outflowing water by tidal.act@`on on the sills. This water has a, density range, of about 24.94 to 26.27 in F gma-t units. In the sua-mer the 0 water occupying the same position has salinity of 32 /oo at 50 m Increasing 0 ..to about 33.9 /11 -at depta and a temperature structure that varies from 80C at 50 m down to about 6.30C at depth. This water has a density range of about 24.94 to.26.67.' Clearly the densest water available for transport into the Straits at depth to be mixed with the outflowing surfacewateris found during the summer. Of equal importance is the higher salinity of the near surface water with which the deep water mixes during the late summer. This higher surface salinity is, of course, a result of the reduced freshwater discharge at this time of year and the deep water from the basins that is being displaced by the incoming dense water. Thus, the densest water available at the sills in Puget Sound to displace the water at depth in the deep basins behind the sills is formed during late summer. In a season when coastal upwelling is particularly intense and widespread, and precipitation is low, a greater quantity of denser water can be formed to act as a flushing agent. If precipitation is high during' a summer and coastal winds do not promote strong upwelling, there is a chance that an insufficient qunntity of the dense water will be produced to thoroughly flush the deep isolated basins of a system such as Puget Sound.. The small shallow harbors having direct contact with the ocean along the Washington and Oregon coast are not as dependent on the quantity and density of the intruding seawater as Puget Sound is. These embayments do not have deep basins behind isolating sills that act as catch basins for dense water. The ratio of tidal prism volume to volume of water at MLW stand is large indicating that a considerable portion of the volume of the embayment at MSL is removed and aeded each tide cycle. Their extensive shallows and exposure to coastal winds, as well as the turbulence generated in &the tidal slCream at their entrances, combine to aid in vertical mixing and promoting exchange between the tidal prism and the residual water left at each low tide. The dilution of these shallow harbors "y their rivers produces strong vertical density structure near the rivers that rctards vertical mixing. The seasonal change in the coastal water present off the mouths of these harbors and bays, however, does have an effect on the water properties Within-the embayments. In the wintertime coastal precipitation increases the-flew of the rivers into these harbors to decrease their salt content and cause strong density stratification near their heads. In the case of Willapa Bay and Gray's Harbor, the effluent from.the Columbia is directed northward along the coast to occupy a position off their mouths. Thus, in winter, fresh water is available to the harbors L:om both the landward and seaward side. In the summer the river discharge into the heads of these two harbors is reduced, and ahigh salinity-low temperature upwelled water is present off their mouths. This means that seasonally a fairly large fluctuation in @salinity can occur while the temperature is buffered. In the winter,water temperatures are controlled by local climatic conditions and by the temperature of freshwater sources. In the summer, however, the increase in temperature due to solar heating of the bay is somewhat offset by the introduction of the low temperature upwelled coastal water. Inspection.of the data available in Willapa.Bay and Gray's Harbor at midbay position shows that considerable scatter in surface and salinity values is found at the surface. These data, however, have been collected at all tidal stages And reflect a trend of elevated temperatures and lowered salinities during ebb stages and lowered temperatures and elevated salinities during flood,periods.in the summer. In the winter the ebb produces lowered temperatures and salinities, while the floodstage elevates both temperature and salinity. Inthe summer an oc!@-asional data point will show a very low temperature and high salinity, indicating the resence of upwelled oceanic water at the mid-channel obaervation point. -9- Temperature and salinity data uncorrected for tidal stage in Willapa Channel (Bendiksen).can be used to construct a T-S envelope that shows the seasonal change in water characteristics. The limits of salinity and temper- ature changes found in such an envelope may be used to judge the fitness of the water for sustaining a biopopulation. As an examplethe adult Pacific oyster Oateria gigae has a known tolerance range to temperature and salinity. The larval stage has a smaller tolerance range fcr survival. This oyster also has a required temperature for spawning. These tolerance limits also can be drawn on a T-S diagram and superimposed on the seasonal T-S envelope for a harbor. It is easy to understaad from the comparison of these two envelopes that the summer introduction of cold upwelled coaRtal water into the harbor acts to suppress the temperatures below that required by the oysters for maintenance of the larval stage or reproduction at the mid-channel location. Thus, intensive coastal-upwelling at a critical period may destroy the larvae or not allow reproduction to occur. During summer the temperatures of the shallow reaches remote from the mid-channel may or may not rise sufficiently to allow survival and spawning. Although I cite Willapa Bay here, similar processes occur at the other harbors along both the Oregon and Washington Coast. However, iv harbors other than Willapa Bay and Gray's Harbor, dilu- tion occurs primarily from rivers entering the heads ci the estuaries. There Is no single large river such as the Columbia to provide additional coastal wintertime dilution at their mouths. The estuary of the Columbia River Interacts with the open sea quite differently from the embayment-type estuaries where inflow and outflow are primarily tidal. In the Columbiz estuary the large river flow limits the intrusion of a osltwater wedge at depth keeping it short of its fall line. The normal intrusion of the salt wedge is limited between Tongue Point and the sea. The large vertical velocity shear between the seaward-moving river water and the Intruding saltwater wedge acts to-maintain a sharp boundary between these two waters across which seawater is entrained upwards into the more turbulent mixed surface effluent. This ernsion'of saltwater from the wedge requires that the salt wedge be replenished. Thus, the inflow of saltwater into the river channel on the flood exceeds that required to movet wedge upstream. Outside of the river mouth, the flow of effluent extend- Ing to a depth of about 15 m also generates a velocity shear and entrainment of saltwater from below that is used to increase the salinity and volume of the-effluent. Both within and without the estuary, the salt and water entrainment p romote a localized upwelling.of deep.er.water immediately around the mouth-of the river and sea-fard of the mouth under the issuing jet. This upwellIng Is highly localized and is driven by processes unrelated to those affecting the more.widespread wind-driven upwelling. The velocity shear up- arge when entrainment in- welling should be strongest at. periods of high disch creases, The foregoing discussion establishes in general terms the manner in which the circulation and changes in the properties of coastal water control in part the physical.processes in the bordering estuaries. We now need to consider some of the other aspects of the interplay between the-ocean and estuaries. The Nutrient and Gas Exchange Between Coastal and Estuarine Water. Not only are water, salt, and heat exchanged between the estuaries and the coastal zone, but also all other dissolved substances carried in the water One.class of substances of importance to the biological populations is nutrien another is the dissolved gasses. Other products such as pollutants, which ara also important, will be neglected here. The mosc important of the dis- solved gasses is oxygen. It is obvious that the displacement of the isolal deep basin water behind the sills in Puget Sound by the intruding dense vat in late summer also provides a mechanism by which aeration at depth is accc plished. However, the-ox ygen concentration of the intruding upwelled watex at Pillar Point during the summer is low at 0.25 to 0.10 mg-at/L. Subseque mixing on the sills elevates this-level to about 0.35 mg-at/L. The winter- time oxygen concentra tions of the intruding water which has its source at lesser depths in the sea are higher, ranging from 0.45 to 0.25 mg-at/L. In late summer the intruding water, when mixed over the sills, has an oxygen content of about 00.4 mg-at/L. This oxygen is then carried to depth in the flushing process. If flushing of this deep water is not complete, then insufficient aeration and removal of accumulated organics and nutrients occi at depth. Within tte estuaries, land drainage and sewage disposal contribute a nutrient supply to the surface waters. As an example here, the Metro System of Seattle alone contributes on the average 2,730 lbs-/day of nitrate- nitrogen, 8,260 lbs/day of ammonia-nitrogen, 5,200 lbs/day of total phosphoi and 4,200 lbs/day of orthophosphate as phosphorus to Puget Sound. An eati- mate of.the total nutrient supply to Puget Sound and other estuaries is not available at this time. The coastal ocean water thatenters the estuaries at depth also acts as a source of nutrients. It was stated earlier that the summer transport of seawater into the Straits of Juan de Fuca as estimated 4 3 1 from continuity was 26 x 10 m sec- . The inorganic phosphorus-phosphate conteat of this water averages about 2.5 ug-at/L. This means that about 6.5 X 108 Pg-at sec-1 is delivered by advection to.the Strait from the sea. -12- An outward transport of'nutrients in the surface layers is also occurring. -The.h.arbors bordering the open coast also exchange dissolved gasses and nutrients with the coastal water. The amount of exchange is sensitive to the-type of coastal water lying at the harbor mouth. During winter the coastal water is oceanic surface water mixed with the effluents of the local rivers. This water is usually well aerated by the stronger winter winds and wave Action. Its low salinity, combined with wind mixing, tends to produce moderately high dissolved oxygen levels (0.5-0.6 mg-at/L). Its nutrient content Is controlled in part by the typical concentrations found in the oceanic surface water, 5.50 ug-at/L for nitrate and 1.0 Ug-at/L for inorganic phos- phate. The river water present as the diluting agent may also add its contri- bution, of nutrients if the river is a t@ource of these materials. In the summer when upwelling of subsurface water prevails under the lighter northerly winds, oxygen concentrations of the coastal water may drop appreciably and nutrient levels increase. Oxygen concentrations at depths where access can be gained into the estuaries can be as low as 0.2 to 0.3. mg-at/L. A specific example may be cited here when in August of.1963 ,saumDles were taken along the coast between Gray's Harbor and Long Beach. In 15 m of water off Grayland, the samples taken indicated that the seawater at 10 m depth had a temperature of 8.22 0C, a dissolved oxygen content of 0.236 u&-at/L,and a salinity of 33.2 0/oo. The collecting of samples on this occasion was prompted by a shellfish kill along the ocean beaches*a short time before. If mixing and aeration of upwelled coastal water in the entrance zone to the harbors or along the ocean beach are not sufficient, the bio- populations may be subject to both depressed temperatures and low oxygen values. The nutrient values of the coastal upwelled water exchanging with the estuaries are elevated during the summer because of its deeper source. Concentration values of 25 pg-at/L for nitrate, afivefold.increase over winter levelst.are possible with a twofold increase of inorganic phosphate to 2 ug-at/L. Concentrations may be diminished to lower levels by in eitu biological utilization near the sea surface if the upwelled.water. is retained in the ,,..,photic zone prior to its exchange with the estuaries. Conclusion. Estuarian and coastal zone processes are interdependent. The estuaries demand water from the coastal zone for tidal processes and to maintain.their average budgets of salt and water.. The type of water present in the coastal zone to meet these demands is governed by coastal and oceanic conditions, and in the case cited here, is closely related to seasonal climatic changes. The presence of dense water at the estuarymouth increases the flushing potential of the deeper well-isolated basins by.gravity flows, whereas the presence of less dense water does not. Mixing processes At the mouths of estuaries or@ across internal sills within estuaries that are depeneent on tidal stream flow combine the inflowing oceanic water at depth with the outward-flowing dilute surface water in the et'Wary. Thus, the strength of the tidal currents and topography, combined wk;h theproperties of the surface water, also enter into the problem of flushing and exchange of water properties. -It is a complex interacuion dependent on many variables. Because of this, each estuary or embayment is unique unto itself and reacts to the whims of nature and man .alike. REFERENCES Barnes, Clifford A., A. C. Duxbury, and Betty-Ann Morse, In Press, The Circula- tion and Selected Properties of the Columbia River Effluent at Sea, Bio- environmental Studies of the Columbia River Estuary and AcUacent Ocean Region, (D. L. Alverson and A. T. Pruter ed.), U. S. Atomic Energy Commission Publication. Budinger, T. F., L. K. Coachman, and C. A. Barnes, 1964, Columbia River Effluent in the Northeast Pacific Ocean, Z961, Z9.62: Selected Aspects of Physical 'Oceanography, University of Washington, Department of Oceanography Technical Report No. 99, Seattle. ..Department of Oceanography, 1953-54, Puget Sottnd and Approaches, A Literature Survey, Vol. I, II, IIr., University of Washington, Seattle. Duxbury, Alyn C., In Press, Variability of Salinity and Nutrients off the Columbia River Mouth', BioenvironmentaZ Studies of the Columbia River Estuary and AcUacent Ocean Region, (D. L. Alverson and A. T. Pruter ed.), U. S. Atomic Energy Commission Publication. Duxbury, Alyn C., Betty-Ann Morse, and Noel McGary, 1966, The Columbia River Effluent and its Distribution at Sea, University of Washington, Department of Oceanography Techical Report No. 156, Seattle. Morse, B.-A., M. G. Gross, and C. A. Barnes, 1968, Movement of Seabed Drifters near the Columbia River, Journal of the Waterways and Harbors Division, American Society of Civil Engineers, 94(WWI): 93-103. Redfield, A. C., 1950, Note on the Circulation of a Deep Estuary-the Juan de Fuca--Georgia Straits, Proceedings of the CoZZoquium on the Flushing of Estuaries, Woods Hole Oceanographic Institution: 175-177. Stefansson, U., and F. A. Richards, 1963, Processes-Contributing to the Nutrient Distribution of the Columbia River and Strait of Juan de Fuca, Limnology and Oceanography, 8(4):394-410. Washington Department Fisheries, Observations of Seawater Temperatures, Density, and Salinity, State of Washington 1957-1957, Hydrographic Data, Vol. 1, No. 2. FIGURE CAPTIONS Fig. 1--Surface Salinity and direction of surface flow in the Northeast Pacific ocean. Fig. 2--Dynamic topography of the near coastal zone, summer conditions. Fig. 3--Dynamic topography of the near coastal zone, winter conditions. Fig. 4--Mean surface wind vectors by month, 1961-1963. Fig. 5--Frequency of northerly and southerly componient winds by month. Fig. 6--Average direction and magnitude of monthly Ekman transport, 1961-1963. Fig. 7--Generalized distribution of Columbia River effluent as indicated by surface salinities, summer condition. Fig. 8--Generalized distribution of Columbia River effluent as indicated by surface salinities, winter conditions. Fig. 9--Release points and hypothetical paths of seabed drifters along the Washington coast. Fig. 10--Temperature and salinity cycles at Pillar Point, Strait of Juan de Fuca, February 1953--March 1954. Fig. U-Surface eaZiniti_,c and temperatures observed in WiZZapa Channel (Bendik8en) Z954. Fig. Z2--Optimum saZintiy and temperature ranges for 0. gigas the Pacific Oyster. Fig. Z3--A comparison of opti-7um salinity and temperature conditions for 0. gigaq and.surface conditions observed in WiZZapa Channel. Fig. Z4--VerticaZ salinity structure in the Colwnbia River estuary, August Z963. Fig. 15--DiesoZved Oxygen content, mg-atlL, in the Strait of Juan de Fuca, July Z953. Fig. 16--Di8solved Oxygen content, mg-atIL, in the Strait of eTuan de Fuca, February Z95 J. Fig. 17--Diesolved inorganic phosphate content, ug-atIL, July Z953. 1600 1400 COLUMBIA RIVER DRAINAGE BASIN 32 HANFORD 3P SALINITY, %* DIRECTION OF FLOW 32, Ry 32.5- % + + 33 32 31 % + + 40 34 *lb 1506 140* 130o 120o Vf Ll us LM LM ku L86 US 10 ML 4r 7 Cftw. cm sec-I rs 6-25 JULY 1961 A 11 - 14 JULY 1961 0 STATIONS DEEPER THAN 1000 METERS FI-q *Lao L30 %I um L30 Lo L30 nm a- 7' On lk@ Ir cm sec-I 23 JANUARY- 7 FE13RUARY 1962 1962) + 3-5 FEBRUARY 1962 0 STATIONS DEEPER THAN 1000 METERS ----------- -L-j -----I------- ....... I ---- 1---, -A ..... ........ .3c. '20. 1300 1280 126* 1220 DEC NOV F 'A 4fr 4114- J,4N OCT MAR APR MAY SEP JUN UG JUL FEB Dr--C 460- NOV X 60 jAN T-YAR APR MAY SEP AUG JUN JUL jIf FEB -440 DEC NOV JA MAR OCT APR MAY SEP 420- AUG Q0 2 4 6 8 10 WIND SPEED IN KNOTS JUL IJUN L GRID POINTS 1300 1280 1260 t240 122* E 5 OCT T APR MAY SEP AUG JUN NA 100 NORTHERLY WINDS > < 0) 50 0-2. 0 w 50 10 SOUTHERLY WINDS 100 'A M J J A S 0 N D J F M 130* 1200 126* 124* 122* -T- --T 4w 48* 4B* AUG JAN JUL JUN APR MAR FEB SEP OCT DEC MAY NOV 46* 446a JAN JUN )APR MAY FEB SEP MAR DEC OCT NOV 440- 440 JUL JUN JAN AUG DEC MAY APR NOV FEB OCT 420- 42' 0.2 OA 0.6 0.8 LO MAR METRIC TONS PER SEC PER METER GRID P(WITS 130* 1280 126* 1240 1220 132' 13cv. 1213. f26- 124- 48-1 WAS" 0, L AP4 e., 4V 46- 26 27 28 44-- 28 ORE -44- It% %% %% 32 4r 4r CALIF -40, 30, 128. 126- 124- 130* 129. F26' 124- I -ci. U.S. ell, WAS" Ir 2 WILLAPA 46' 44-- 4 ------- CALIF . - 120. VANCOUVER ISLAND S7;9417- A4/c @914 X RELEASE POINTS AND HYPOTHETICAL PATHS > RIVER MOUTH < 40 METERS > 40 METERS x NO RECOVERIES 0 50 100 KILOMETERS IS53 V A v .1 1 s 0 0 1 to - so 40 Go zoo@- Soo IL 120 w 4000 Mo so 6w TEMPERATUPE *C 19" F 9A AA to i J A S25t 0 IS 0 a f V :,r4 .20 do *0 go too % I % am so 52 Joe, J!j- z 33 %% 00 % 4000 bo M% c34 no wo 13 so wo SALINITY %e IMMET sou" -PILLAR POINT TEMPMTLME AND SALINITY CY=S 40 30 10/19 3/18 9 :Z- 2 0 5/22 7/20 6/15 11/20 4/21 10 20 30 TEMPERATURE, OC P 9 5/22 6/15 0 11/2 gi go's LARVAE 40 SPAWNING TEMP. 23.30 30 ADULT Z 20, cn 10 10 20 TEMPERATURE, *C Mo. Eli m M.-M, mom mo m. LARVAE 40 SPAW NING 30 23.3 10/19 8/19 3/18 ADULT 9/29 20 5/22 z .7/20 6/15 11/20 4/21 10 10 20 30 TEMPERATURE, OC 9/29 5/22 P65 JET T PT 15 10 20 30 20 - 31 2 FLOOD STAGE 40- 5 C- 2015 05 32 31 25 33 EBB STAGE 40- SALN" Ma) CoLUVBA FaVER MOUTH AUGUST IO-CZ 1,q STRAIT OF JUAN DE FUCA A SrA *V. 770 rat M4 ?as 0 ode no,, 50 .40 %%% do 100 .2D % w % .25-" w ADMIRALTY INLET Go SILL z 150 VICTOPdA-GR N PT SI LL 8200 2.50- 300 STRAIT OF JUAN- DE FUCA A Wo Am 50 .50 50- .50 749; --:45.., ADMIRALTY INLET SILL 150 VICTOPJA-GREEN PT SILL 300- lu!Od JOiPd CQ S8313W NI Hld3G L J DATE DUE GAYLORD No. 2333 PRIMED IN U.S.A. COASTAL ZONE WORNAMON CEWER 36668141