Geomorphic Processes of a Drowned River Valley, Lower York River Estuary, Virginia

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Dissertations, Theses, and Masters Projects Theses, Dissertations, & Master Projects

1976

Michael Joseph Carron College of William and Mary - Virginia Institute of Marine Science

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Recommended Citation Carron, Michael Joseph, "Geomorphic Processes of a Drowned River Valley, Lower York River Estuary, Virginia" (1976). Dissertations, Theses, and Masters Projects. Paper 1539617467. https://dx.doi.org/doi:10.25773/v5-yk0p-2d21

This Thesis is brought to you for free and open access by the Theses, Dissertations, & Master Projects at W&M ScholarWorks. It has been accepted for inclusion in Dissertations, Theses, and Masters Projects by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. GEOMORPHIC PROCESSES OF A DROWNED RIVER VALLEY: LOWER YORK RIVER ESTUARY, VIRGINIA

A THESIS

Pr e se nt ed to

V irginia Institute of Marine Science

The College of W illiam and Mary in V irginia

In Pa r t i a l Fulfillment

Of the Requirements for the Degree of

Master of Arts in Marine Science

ichael Joseph Carron

LIBRARY o f tho VIRGINIA INSTITUTE of .M A R IN E SCIENCE ProQuest Number: 10626097

INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted.

In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if materia! had to be removed, a note will indicate the deletion. uest.

ProQuest 10626097

Published by ProQuest LLC (2017). Copyright of the Dissertation is held by the Author.

ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 - 1346 APPROVAL SHEET

This thesis is submitted in partial fulfillment

the requirements for the degree of

Master of Arts

1(i ^ i W r * , Michael J. Carron

Approved,

Dr'-Chairman

h.D.

C v v ft c/

A jK jJIa-ikX'C LVv ClT>— \ Gerald H. Jol^jison, P h .D .-Geology College jtff William and Mary

M m V. Merrm e r , Ph.D.

Mayn ard M . Nichols, Ph.D. TABLE OF CONTENTS

Page

Acknowledgments ...... IV

List of Tables ...... v

L ist of F i g u r e s ...... VI

Abstract IX

Introduction a s s s 2

What is an Es t u a r y ?. . I I I 5

The No n -Estuarine River 11

The Study Area GEOGRAPHY AND GEOLOGY...... m PRESENT SEA LEVEL RISE ...... 26 CLIMATE...... 26 BATHYMETRY ...... ■ 30

Physical Properties SALINITY DISTRIBUTION. ,...... 32 CURRENT VELOCITY DISTRIBUTION...... 38 WAVE REFRACTION...... 47

F ield Methods SEDIMENT SAMPLING AND ANALYSIS 61 SEISMIC PROFILING...... 62 NAVIGATION ...... 62

Bottom Sediments and Processes 63 FILL AND SCOUR ...... 73

The Stratigraphic Record of the Study Area ...... 90

DISCUSSION AND CONCLUSION...... 102

Summary i.i.iiiii.i.ii.ii.i.iii 109

Ap p e n d i x ...... 110

B ibliography ...... I • I 111 ACKNG WLEDGMENTS

The author wishes to express his gratitude to

John Zeigler, Hobert Eyrne and Victor Goldsmith for their valuable support of this project. The cooperation and enthusiasm of Maynard Nichols, John Merrlner and Gerald Johnson is greatly appreciated.

Valuable field and laboratory assistance was fjrovided by Steven Shiver, Susan Carron, and Peter Hosen.

IV LIST OF TABLES

Table Page

1. River variables during different geologic time spans...... 12

2. Date and slack water periods used in average salinity profiles...... 37

3. Average depths (meters) across the lower York River transects Y1-Y5...... 84

4. River variables during the estuarine time span...... 108

v LIST OF FIGURES

F igure Page 1. Color IR photograph of lower York River Estuary study area...... Frontispiece

2. Lower York River Estuary study area...... 4

3. Ideal average salinity and velocity profiles for Type A,B,C, and D estuaries...... 10

4. The lower Chesapeake Bay system...... 16

5. Map showing the major geomorphic features in the study area...... 20

6. Cross-section of the York River at Yorktown, Virginia (modified from Hack, 1957)...... 22

7. Sea level curves: A. 40 x 10^ years BP to Present according to Fairbridge (1960) ...... 24 B. 20 x 10^ years BP to Present according to Shepard (1961)...... 24

8. A. Wind speed and direction for the period 1936 to 1970 for Langley AFB, Virginia.. 29 B. Percentage distribution for winds over lOkts (5m-sec“l) for the period 1936 to 1970 for Langley AFB, Virginia.. 29

9. Salinity sample locations...... 34

10. Average salinity profiles for stations Y3.6, Y4.8, Y6.4, and Y10.1...... 36

11. Current meter array locations...... 39

12. Axial current velocity averages for current array locations Y-2A, Y-2B, and Y-2C.... 42

13. Axial current velocity averages for current array locations YV-2A, YV-2B, and YV-2C. 43

VI L ist of F igures (c o n t i n u e d )

F igure Page

14. Lateral current velocity averages for current array locations Y-2A, Y-2B, and Y-2C.... 44

15. Lateral current velocity averages for current array locations YV-2A, YV-2B, and YV-2C..45

16. Lateral and axial velocities, averaged for twenty minutes, for current array Y-2B, beginning 1020EDST 22 Aug., 1973...46

17. Wave refraction diagram (T=2, Az=270°T)...... 51

18. Wave refraction diagram (T=2, Az = 135°T)...... 52

19. Wave refraction diagram (T=3, Az=270°T)...... 53

20. Wave refraction diagram (T=3, Az=135°T)...... 54

21. Wave refraction diagram (Wind 10kts/270°T)...... 55

22. Wave refraction diagram (Wind 10kts/135°T) ...... 56

23. Wave refraction diagram (Wind 25kts/270°T)...... 57

24. Wave refraction diagram (Wind 25kts/135°T)...... 58

25. Method of determining direction and relative strength of longshore current...... 60

26 . Sediment sample locations ...... 67

27. Distribution of sand and larger sized particles... 68

28. Distribution of silt sized particles...... 69

29. Distribution of clay sized particles...... 70

30. General bottom types...... 71

31. Sediment nomenclature graph (after Shepard and Moore, 1955)...... 72

32. Ranges used in fill and scour investigation...... 7 4

vii List of F igures (c o n t i n u e d )

F igure Page

33-37. Transects Y1-Y5, containing information from hydrographic surveys between 1857 and 1973...... 76-80

38. Cross-sectional areas at mean low water (MLW) on ranges Y1-Y5 of the lower York River Estuary 8 2

39. Fill and scour for ranges Y1-Y5...... 86

40. Range Y3 cross-sections (1857 and 1973)...... 88

41. Possible ebb-tide eddy at Gloucester Point...... 89

42-43. Sample sub-bottom profiles of study area.... 93-94

44. Top of Tertiary facies-lower York River Estuary (West)...... 95

45. Top of Tertiary facies-lower York River Estuary (East)...... 96

46. Sand and gravel isopach map-lower York River Estuary (West)...... 97

47. Sand and gravel isopach map-lower York River Estuary (East)...... 98

48. Holocene mud isopach map-lower York River Estuary (West)...... 99

49. Holocene mud isopach map-lower York River Estuary (East)...... 100

50. Stratigraphic sequence of sediments below river b e d ...... 101

51. Paleotopography on the top of the Yorktown Formation (Tertiary) in the Poquoson East, Poquoson West, and Yorktown Quadrangles (from Johnson, 1972)...... 103

52-56. Appendix B----- Survey to survey cross-section comparisons for transects Y1-Y5..... B1-B16

viii ABSTRACT

An investigation of the genesis of the geomcrphology of the lower York River Estuary, located in the coastal plain of Virginia, bv the use of seismic profiles,- sediment distributions, analytical wave refraction computations, bathymetric analysis and hydraulic analysis, results in a list of variables affecting estuarine morphology.

Seismic profiles demonstrate the presence of paleochannels, lined with coarse material, indicating fluvial, rather than estuarine, flows in past times. Paleochannels, coincident with the present thalweg, are located along with presumed paleomeanders.

Bottom sediment distributions range from fine sands in the shallow submerged-terrace regions to siltv-clays in the d e e p s .

Average current velocities are similar to the bimodal distribution expected for a moderately stratified estuary, but reversals in the flow field were observed in some channel- margin regions. Significant lateral flow is observed.

In the bread geoinorphic sense, the morphology of the f 1 u v i al-ancestrol York River and those processes causing its morphology govern the location and direction of the present estuary.. The present estuary is the drowned river valley of the glacial-Pieistocene York River, the drowning caused by a rise in sea level.

The morphology on a local basis is controlled by the rate of sea level rise, estuarine hydraulics, wind waves and swell, and biologic activity (including man) «

IX GEOMORPHIC PROCESSES OF A

DROWNED RIVER VALLEY: LOWER YORK RIVER ESTUARY, VIRGINIA INTRODUCTION

The morphology of a river, its form and structure, is influenced by many geological and hydrological factors. In the classical riverine sense, the influences are primarily fresh water runoff, the geologic evolution of the river basin, its lithology and structure, and the initial relief of the river valley. Estuarine rivers are additionally influenced by tidal processes, water density variations, sediment influx, sea level changes and by wind waves and ocean swell.

My objectives were to describe the present morphology, the processes that have caused the present morphology, and the processes which are active today in either maintaining or changing the present morphology of an estuarine river that has undergone extensive geologic change in recent time.

Some of the basic questions which confront an investigator of estuarine river morphology are:

1. What is the present estuary's location, channel orientation, and bathymetry? How have these changed in the past and how are they presently changing?

2. What is the bottom sediment composition of the area and by what processes were the sediments deposited?

3. What is the stratigraphy of the sediments in the river bed and what can be interpreted from this stratigraphy?

2 3

4. What external processes(meterological, man-made, external sediment influx) have been and are presently active

in changing the morphology?

5. What role does hydraulics play in changing or maintaining the estuarine river morphology?

6. What major variables are ultimately responsible

for the estuary1s morphology?

I have attempted to answer the above questions by under taking a detailed study of a section of an estuarine river

system, the York River in Virginia (Figures 1 and 2) .

WHAT IS A.4 ESTUARY?

Until recently geomorphologists had no universally

accepted definition of an estuary, and although there were

no great controversies, this lack of consistency in scientific

writings was awkward. The term 'estuary' has been defined in

many different and, in most cases, limited ways. A few

examples are:

1. A tidal bay formed by submergence or drowning of the lower portion of a non glaciated river valley and containing a measurable quantity of sea salt (Baker et a l . , 1966) .

2. A drainage channel adjacent to the sea in which the tide ebbs and flows. Some estuaries are the lower courses of rivers or smaller streams, others are no more than drainage ways that lead seawater into and out of coastal swamps (American Geological Institute, 1974).

3. The wide mouth of a river where it is met and invaded by the sea, especially in a depression of the coast (Funk & Wagnalls, 1962) .

All of these definitions allude to a similar meaning, but each excludes certain bodies of water that are generally considered estuarine: fjords in definition (1), small-tidal or non-tidal rivers in definition (2), and estuarine bays in definition (3) .

Pritchard (1967) overcame most of these difficulties by defining the estuary as

5 6

...a semi-enclosed coastal body of water which has a free connection with the open sea and with in which sea water is measurably diluted with fresh water derived from land drainage.

This definition is general enough to include all bodies of water generally considered estuarine.

Perhaps one problem associated with the lack of a usable definition of an estuary prior to the mid-sixties was the absence of extensive morphological studies of estuaries.

Anhert (1960) noted that to the student of riverine morphology the estuaries are too 'marine' and to the student of coastal morphology they are too 'fluvial'. This occurs in spite of the fact that 8 5 percent of the Gulf and Atlantic coasts and

15 percent of the Pacific coasts are estuaries or lagoons^

(Emery, 19 67).

The estuary presents an interesting problem to the geomorphologist. While it is generally believed that rivers always flow 'down to the sea', this quite often is not the case. For hundreds of years mariners have faced the problem of having to wait for an ebb(falling) tide to set sail, because the currents in the rivers leading to their ports- of-call often flowed upstream at a velocity greater than the speed of their vessels. Noting this, one is tempted to say that the flow in the estuarine or tidal river is therefore a simple in-and-out motion corresponding to the flood and ebb tides, with the ebb flow a little stronger to compensate for

^water body behind barrier islands (AGI, 1974) 7

the added fresh water runoff of the river. Often in the

surface layers of the estuary this is close to what happens.

Nevertheless., this can be very misleading, for what is happen

ing near the bottom is often just the opposite of what is

happening on the surface.

Current patterns in estuaries are extremely complex and

V c i r i e d . In order to simplify studies of estuaries they have generally been divided into four classes.

Classes of Estuaries

Pritchard’s definition of an estuary covers a wide range of morphological and hydrological situations, from coastal lagoons (provided there is a significant salinity drop between the lagoon and the sea) to fjords, with a multitude of situa tions falling in between. Pritchard (1952, 1955, 1967, and

1971) presented two useful schemes to classify estuaries based on estuarine circulation patterns, which result from the fact that, in general, estuaries are the meeting place for cold highly-saline dense water and warm re.latively-f resli, and there fore , less dense water.

In general, the ratio between the fresh water runoff and the tidal prism2 determines the type of estuary. If this ratio is high the result is usually a highly salinity-stratified or

Type A(salt wedge) estuary. An example of this is the lower course of the Mississippi River. If the ratio is low and the

o High water volume-low water volume 8 estuary is very wide in relation to its depth, the result is generally a vertically homogeneous or Type C estuary. If the fresh water to tidal prism ratio is low and the estuary is narrow and deep, a horizontally homogeneous or Type D estuary results.

In regions where neither the tidal prism nor the fresh water runoff dominate, the stratification is erased because of vertical mixing between the fresh and the salt water masses; consequently, both layers of weter exhibit a greater salinity as measurements are taken seawardly. This type of estuary is classified as moderately stratified or partially mixed (Type B ) .

The Chesapeake Bay and the lower courses of its tributaries all fall within this classification.

As a result of the different salinity distributions, the four estuary types discussed above exhibit widely different current velocity profiles. Figure 3 illustrates the salinity and velocity profiles for 'ideal0 estuaries of all four types. 9

F igure 3. Id e a l a v e r a g e s a l i n i t y a n d v e l o c i t y PROFILES* FOR:

A. Type A-Highly s a l i n i t y -s t r a t i f i e d OR SALT WEDGE ESTUARY.

B. Type B-Mo d e r a t e l y s t r a t i f i e d or PARTIALLY MIXED ESTUARY.

C. Type C-Ve r t i c a l l y Ho m o g e n e o u s ESTUARY.

D. Type D-Horizontally homogeneous ESTUARY.

*Afte r (d y e r ,1973) SALINITY VELOCITY UPSTREAM DOWNSTREAM .5Z OCEANIC J .. V

" 'L E F T RIGHT * LEFT RIGHT/ / / > / RIGHT LEFT

3d THE NON-ESTUARINE RIVER

The non-estuarine river has been the subject of exten sive research. As early as the late nineteenth century land mark papers were being written on the subject of the role of rivers in the geological cycle (Gilbert, 1880; Davis, 1899).

Fluvial processes have been the major subjects of three standard geomorphology text books (Thornbury, 196 9; Morisawa,

1968; Leopold et a l ., 1964). From the wealth of studies on non-estuarine rivers, Shumm (1962, pp. 366-395) has composed a listing (Table 1) of the variables that influence river morphology for three different time scales.

In table 1, geologic time refers to a time span en compassing a complete erosion cycle, say, 10^ years. Accord ing to Shumm, when viewed from this perspective the river is an open system undergoing continued change with elapsed time being the most important independent variable.

Graded time refers to a time in which some sort of dynamic equilibrium exists. Shumm suggests 100 or 200 years for this time scale. During this time, relief, climate and vegetation determine the average hydraulics of the system.

Hydrology (mean discharge of water and sediment) becomes the major independent variable upon which channel morphology depends.

11 TABLE 1 RIVER VARIABLES DURING DIFFERENT GEOLOGIC TIME SPANS*

Variables Status of va riables DURING DESIGNATED TIME SPANS

Geologic Graded Steady

1. Time (stage) INR NR 2. Initial relief INR NR 3. Geology (lithoiogy, structure) I I I 4. Paleoclimate I I I 5. Paleohydrology D I I 6 . Relief or volume of system above baseline DI I 7. Valley dimensions (width, depth, slope) DI I 8. Climate (mean p pt., temp., seasonality) X I I 9. Vegetation (type and density) X I I 10. Hydrology (mean discharge of water and sediment) X I I 11. Channel morphology X D I 12 . Observed Qw Qs (reflecting meteorological events) X X D 13. Hydraulics of flow X X D

I = independent D = dependent X = indeterminate NR = not relevant

*From Shumm, 196 7 13

Steady time is defined by Shumm as a week or less. Dur

ing this time scale none of the variables change with time,

although drastic modifications to the morphology may take

place, such during a flood. These modifications are not

permanent and may be thought of as perturbations from the

mean channel dimensions. Likewise, water and sediment dis

charge rates during floods are only temporary and soon approach

the seasonal mean.

It must be made clear here that the terms 'independent'

and 'dependent5 do not strictly follow the mathematical inter

pretations of the same terms. In a physical system such as a

river only the first four variables in Table 1, the initial

conditions, can strictly be considered independent. All other

variables receive feedback to one degree or another with the

more drastic effects of feedback occuring during the shorter

time scales.

I do not propose to argue the merits or shortcomings of

Table 1, but rather shall discuss these variables (and ethers)

as they pertain to an estuarine river. I will suggest that

a fourth time scale, 'estuarine', be added to the list and have

a length of perhaps 50,000 years or the time that a certain part of a river is in the estuarine phase.

LIBRARY ^ o f the V ir g in ia in s t it u t e; of x. MARINE SCIENCE J* THE STUDY AREA

Geography and Geology

The Lower York River in Virginia is part of the Chesa

peake Bay System (Figure 4), an extensive estuarine complex,

located on the coastal plain of the eastern United States.

The Chesapeake Bay was formed by the submergence of the

dendritic drainage system of the ancestral Susquehanna River

(Shepard, 1973, p. 188; Ryan, 1953, p. 10). The present bay

system contains six major rivers, all of which enter the

bay on its western side. These are, from north to south: the

Susquehanna and Patuxent rivers of Maryland; the Potomac River which froms the boundary between Virginia and Maryland; the

Rappahannock, York, and James rivers of Virginia.

The York River is formed by the confluence of the Matta- poni and Pamunkey rivers at West Point, Virginia and flows

64km southeast to its mouth at the Chesapeake Bay. The drain

age basin of the York River System is 6900km2 and has an average runoff of 70m3-sec“’l (calculated from Va. Div. Water Res., 1974).

The entire length of the York is tidal and the tidal influence extends 9 6km up the Mattaponi and 6 0km up the Pamunkey (Brown et al_. , 1938) . The average width of the York is 3km with an average depth less than 6m, although depths of over 26m are present.

14 15

FIGURE 4. The lower Chesapeake Bay Sy s t e m , >- CO 17

The specific area of the York selected for this study

is centered at the Yorktown-Gloucester Point Pass and extends easterly to longitude 76°26'W and north-westerly to approx imately latitude 37°18'N (Figure 2) . This 8 x 14km. area is covered by U. S. Dept, of Commerce, National Ocean Survey charts 12241, 12238, and 12243. The land adjoining the study area is covered by U. S. Geological Survey 7.5' quadrangle maps;

Clay Bank, Yorktown, Achilles and Poquoson West. The land area is also partially covered by Va. Div. Mineral Resources

Geologic maps of the Poquoson West and Yorktown quadrangles

(Johnson, 1972).

The York River exhibits six prominent morphological features:

1. an axial channel flanked by broad submerged terraces;

2. sharp change in channel orientation from SE to E at the Yorktown-Gloucester Point Pass;

3. a very narrow constriction at the Yorktown-

Gloucester Point Pass (<\;8Q0m) in spite of high currents

( Im-sec”^-) ;

4. depths exist along the thanweg greater than

20m in areas of apparently low current velocities;

5. no surface meanders between West Point and the Yorktown-Gloucester Point Pass;

6. many islands in the shallows on the north side of the estuary upstream from the Pass. 18

The pre-Holocene sediments in the study area and those

forming the land masses to the north and south consist pri marily of Mesozoic marine-deltaic and Cenozoic marine de posits approximately 400m thick. The Tertiary deposits over- lying the Mesozoic sediments are generally of marine or estuarine origin while the Quaternary deposits covering all of these are shallow marine and estuarine. The pre-Holocene

Quaternary deposits were mostly deposited during the Pleisto cene interglacial ages (Johnson, 1972) and gave rise to a

succession of plains whose surfaces dip eastward and in some cases toward the major estuaries. These plains form the major geomorphic features of the land areas to the north and south of the study area and show the classic coastal plain stair step topography which reflects former high stands of the

Pleistocene sea (Figure 5). The pre-Holocene Quaternary glacial age deposits are primarily sands and gravels which were later covered by Holocene muds. The land areas bordering the

York and thus supplying sediments through bank erosion gener ally consist of a thin layer of soil underlain by the Norfolk

Formation which consists of fluvial and estuarine clayey-sands, beach and nearshore marine sands, and marine silty-sands and sandy-clays. In some localities outcrops of the Yorktown For mation, consisting primarily of marine quartozose fine sands and biofragmental shell beds, form cliffs which border the study area (Johnson, 1972)

According to Johnson (1969), no evidence of significant tectonic movement since the Miocene exists in the study area. IGURE b. Map sho w i n g the m a j o r g e o m o r p h i c FEATURES IN THE STUDY AREA. (SOUTHERN AREA AFTER JOHNSON. 19/Z NORTHERN AREA FROM THIS STUDY). i n

RIVER r o

76 ° 30

s c a r p b o u n d a r y (d a s h e d WHERE INDISTINCT)

✓ INDISTINCT MORPHOLOGIC ^ BOUNDARY 21

Perhaps the most important key to the recent evolution of

the York River estuary lies in the stratigraphy of the sediments

beneath the river bed. Hack (1957) analysed drill records from

the preconstruction bottom analysis for the bridge at the York

town-Gloucester Point Pass. The resulting cross-section (Figure

6), indicates that fluvial and estuarine environments have inter

mittently existed since the early Pliocene. Sand and gravel

deposits indicate the existance of high current velocities and

turbulence such as that associated with a non-estuarine flow

field. This situation can be expected to take place during

periods of extremely low sea levels (<-20m) . Clay and silt

can be expected to be deposited during periods of low current

velocities such as that observed in an estuarine flow field.

The W isconsin Glacial Age

About 103 years BP the temperature of the earth began to drop quickly (probably for the fourth or fifth time in 10^

years). Precipitation falling in the high latitudes was de posited as ice and snow and failed to return to the oceans.

Before this process ended,about 20,000 years BP, close to

5.0 x 10 7 knJ ? of ice and snow had accumulated on the continents, with a resulting sea level drop of approximately 100m (Clark

and Stearn, 1960)(Figure 7A). At this time the continental

shelves were exposed to subaerial weathering, were deeply

incised by streams and were possibly covered with hardwood forests. The present estuaries of the Chesapeake became h-

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F igure 7A. Sea l e v el AO x 1 0 /} ye a r s BP to p r e s e n t ACCORDING TO FAIRBRIDGE (1960),

F igure 7B. Sea l e v e l 20 x H P ye a r s BP to p r e s e n t ACCORDING TO SHEPARD (1961) WITH Fa i r b r i d g e s (1960) c u r v e superimposed FOR COMPARISON. I00--

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entrenched and with the possible exception of the James River were then tributaries of the ancestral Susquehanna River.

Their flow was unidirectional with the water attempting to

O cut its way down to 'base level'-3.

These tributaries of the ancestral Susquehanna probably

did not reach base level, for, according to most researchers

(Fairbridge, 196 0; Curray, 196 0; Jelgersma and Pannekock,

1960; and Shepard, 1960), the sea level trend reversed around

18,000 years BP and the sea level began to rise quickly. Most believe that sea level rose rapidly until about 4,000 years

BP and from that time has slowly risen to its present level.

Fairbridge described a series of Holocene high stands of sea level from 6,000 years BP to present. Shepard (1960) compiled

sea level positions based upon dates of organic material taken from what were presumed to be stable areas (Figure 7B).

In figure 7B Faribridges sea level curve is superimposed upon

Shepard's for comparison.

As sea level rose to approximately 2 0m below its present level (o> 9,000 years BP) , higher salinity water and tidal processes began to change the circulation patterns in the lower

York River. This resulted in the deposition of silt and clay and initiated processes which resulted in the morphology of the

York as it is today.

3The level when the river has smoothed its longitudinal profile and has a grade or slope such that "the slope is delicately adjusted to provide with available discharge and with pre vailing channel characteristics, just the vel ocity required for the transportation of the load required." (Mackin, 1948) 26

Present Sea Level Rise

Data taken from the C&GS tide station located at Glou

cester Point, Virginia (Hicks, 1975, unpublished data) have

shown an average sea level rise of 2.lOmm-yr"! between the

dates January, 1951, and December, 1967. Hicks and Crosby

(1974) using a 40 year record demonstrated that the local sea

level was rising at a rate of 4.63mm~yr“l Hampton Roads,

Virginia, located to the southeast of the study area. This

value is probably more realistic than the 2.10mm-yr”^ for

Gloucester Point, because a 16 year record may not be long

enough to establish a long term trend.

The local sea level rise computed from marograph data

consists of two components, isostatic sea level change (world wide change in the level of the sea as measured from a station

ary datum) and local crustal motion. Holdahl and Morrison (1974)

found an annual crustal subsidence of between 1.2mm and 4.0mm

in the Chesapeake region. At Yorktown, Virginia, in the center the present study area, they found approximately 3.09mm-yr”l crustal subsidence.

Cl i m a t e

The York River estuary lies in the humid subtropical area of the Atlantic coastal plain. The mean temperature of the

study area is 1 5 ° C with a record high of 4 0°C and a record low of ™19°C. The annual precipitation is 112cm and of this less than 2.5cm is in the form of snow (Va. Dept, of Conservation, 1970). 27

Wind data compiled by the Air Weather Service (MATS) of the U. S. Air Force for Langley Air Force Base, Virginia

(located southeast of the study area), indicate, for the period 1936 to 1970, that the dominant wind direction is northerly, while the prevaling winds are southwesterly with the mean wind speed for all directions being 8. 5kts (4. 3m-sec“'l)

(Figure 8A) . Winds of lOkts (5m-sec“"^) or greater have enough energy to cause significant wave action in the estuary.

The percentage distribution for these winds (Figure 8B) is similar to the distribution for all wind speeds. 23

F igure 8A, Pe r c e n t a g e distribution for w i n d DIRECTIONS (SOLID LINE) AND AVERAGE SPEEDS (.DASHED LINE)* EOR_THE PERIOD 1936 to j.9/0 at Langley ArB, Virgin;

F igure 8B, Percentage distribution for wind directions for winds over IOkts" (5m-sec-J) at Langley AFB, Virginia:

^’compiled b y the Air Weather S e r v i c e (MATS) of the U, S, Air Force, N

NW HE 8A

W i—

S C’ 3 1 O k n o t s SW SE

SW ■ SE

FIGURE 8, 30

Ba t h y m e t r y

Probably the most widely used graphic geological device

is the topographic map, which shows the topographic features

of an area as contour lines. The equivalent chart in areas

covered by water, is the bathymetric chart, which presents the

relief and contour of the bed of the water body as measured

from some standard vertical and horizontal datum.

I constructed bathymetric charts of the study area from

the latest U. S. Coast and Geodetic Survey's Hydrographic

Surveys, H7022 (1945), H7952 (1953), and H7953 (1953) updated

with the Corps of Engineers Hydrographic Surveys H010-15-03(4)

and (5) of 1973. The later consisted of five transects across

the York River in the study area. The vertical datum that I

used is mean low water (MLW), with contours drawn at one meter

intervals. My charts, YORK RIVER l(WEST) and YORK RIVER 2 (EAST)

are located in the attached envelope.

There is no records of dredging for channel maintenance

in the main river channel of the study area, although dredging

has taken place at four major pier complexes near the south

bank. in addition, all four piers handle deep-draft vessels

which constantly modify the bathymetry around the piers by

propeller wash. To eliminate confusion and to flag these

particular areas, the piers have been represented by dashed

lines on the bathymetric charts.

There are three prominent bathymetric features in the

study area. The first of these is the existence of wide sub merged terraces in all areas with the exception of the Pass. J1

The slope of the terraces is ususlly less than 1°. The terrace edge generally exists at a depth of 4-5m below the present sea level . This corresponds to sea level approximately

3,000 years BP. Rosen (1976) compared erosion rates with terrace widths in the Chesapeake Bay and found a high cor relation between computed terrace widths and measured widths.

He attributes the existence of the terrace to the decrease in the rate of sea level rise that occured 3,000 years BP,

Second, extremely deep areas (over 2,0m) occur both to the east and to the west of the Pass and are separated from the Pass by shoals at least 6m shallower than the deeps. Third, the area in the Yorktown-Gloucester Point Pass which, in addition to be ing extremely narrow, has bottom slopes greater than 8° (approx imately a 1 to 7 depth to width ratio) on the south side. At: the Pass, the channel, orientation changes sharply from southeast to east. PHYSICAL PROPERTIES

Sal in it y D istribution

Water samples were taken monthly at four stations in the

study area (Figure 9) between January and August, 1973, by

the Department of Physical Oceanography and Hydraulics of the

Virginia Institute of Marine Science. The average salinity

profiles for the four stations are shown in Figure 10. In

some cases all months were not used in the computations because

non-standard depths were given for the samples. In most

cases water samples were taken at two meter intervals. Table 2

lists the months used for each station along with an indication

of high (HWS) or low (LWS) tides for each sampling. In addition

to the average profiles (Figure 10), which were limited to 12m, one sampling at station Y3.6 was taken to a depth of 24m. This

sampling, included in Figure 10 for comparison, is more realistic, because the 'average' profiles at station Y3.6 are limited to the upper and fresher levels of the water column.

The average salinity profiles for stations Y6.4, Y4.8, and, especially, for station Y10.1, approximate the typical salinity profile for a moderately stratified estuary (Figure 3B). Station

Y3.6 shows a salinity profile similar to the homogeneous estuary described by Pritchard (1971), (Figures 3C&3D). However, the

32 33

full salinity profile for Y3.6 at HWS on 17 January has a dis

tribution similar to that of a highly stratified estuary

(Figure 3A) (Bowden, 1967) . It is possible that the average distribution for station Y3.6 would show a similar profile if

samples had been taken to the maximum depth on all samplings. 76°l40' 76n30' \ UJ 00 .j J A K) 0 0 m o UJ N-

Figure 9, Salinity Sample Locations 35

F igure 10. Av e r a g e s a l i n i t y p r o f i l e s for s t a t i o n s

Y3.6, YA.8, Y6.4 a n d Y10.1. DEPTH(m) 24 18-4— 2 4 6 8 0 22 20 18 16 14 12 SALI SALI NITY( 48 Y3.6Y6.4 Y4.8 PPT) W I 973) 3 7 I9 N A J I7 HWS . I Y 3.6 TABLE 2

Date and s l a c k w a t e r per i o d s used in AVERAGE SALINITY PROFILES (H=HlGH, L=Low)

______STATION______Y3.b Y4.8 Y6.A Y10.1

17/1/73CH) 17/1/73(H) 17/1/73CH) 17/1/73(H) 6/2/73(H> 6/2/73CH) 6/2/73(H) 6/2/73(H)

2/3/73(H) No n -s t a n d a r d d e p t h s ------22/5/73(L) 22/5/73(L) 22/5/73CL) 22/5/73(L) 12/6/73(H) 12/6/73(H) 12/6/73CH) 12/6/73CH) 3/7/73 CL) 3/7/73(L) 5/7/73(1) 3/7/73(L) 38

Cu r r e n t Ve l o c i t y D istribution

Two groups of three Braincon savonius-recording-current- meter arrays were deployed and sampled at 2 0 minute intervals^ during six complete tidal cycles during August, 1973. The meters were deployed by the Physical Oceanography and Hydraulics

Department of the Virginia Institute of Marine Science.

The first group, consisting of arrays Y-2A, Y-2B, and Y-2C, was positioned near the Yorktown-Gloucester Point Pass and began recording the morning of 22 August, 197 3. The general distribution of average axial current velocities (Figure 12) in that location demonstrates that a distribution similar to that discussed earlier for an ideal moderately stratified estuary

(Figure 3B) exists. The highest downstream velocity recorded during the six tidal cycles was 0.92m-sec”l at a depth of 0.91m at station Y-2B. The maximum upstream velocity was 0.88m-sec“l at a depth of 15.5m at station Y-2A. The actual velocity distributions are weighted averages for positive (upstream) and negative (downstream) flows. The level of no motion, or depth where the average velocity for a complete tidal cycle is zero, exists at approximately 10.0m for the Y--2 group.

The axial velocity distributions for the current meters placed at locations YV-2A, YV-2B, and YV-2C (Figure 13) on the morning of 27 August, 1973, do not all conform to the velocity distribution expected, for an ideal moderately stratified estuary.

^Actual reading is the average velocity and direction for a twenty minute period, not a true instantaneous measurement. 76° 14 O' 76 *1 3 0 o z CM O LO CO O CD ^ O CM CVl CM o to d!

Figure 11, Current Meter Array Locations 40

The two meter arrays on the flanks of the channel (YV-2A and

YV-2C) had a velocity pattern opposite that expected, while the array placed in the center of the channel had a distribution similar to the ideal. A possible explanation for the anomaly near the channel margins may be the existance of a flow field similar to that observed in a well mixed (vertically homogeneous) estuary (Figure 3C). In the well mixed estuary Coriolis acceler ation causes a lateral variation in the axial flow; the upstream velocities being greater on the right side (looking upstream), and the downstream velocities being greater on the left.

A twenty minute average velocity distribution for station

Y-2B (Figure 16) demonstrates the possibility for the velocity at a particular time at different depths to be bimodal and have a distribution similar to the ideal or average profile expected for a moderately stratified estuary.

The lateral components of flow (Figures 14 and 15) appear to support Dyer's (197 6) contention that significant cross stream flows exist. There is an unexpected similarity between the profiles for group Y-2 and YV-2. The velocity profiles for the mid-channel arrays (Y-2B and YV-2B) both show complex, but similar, distributions. These distributions are probably the result of wind shear and river geometry. F i g u r e 12. Ax i a l c u r r e n t v e l o c i t y a v e r a g e s FOR CURRENT ARRAY LOCATIONS Y~2A, Y-2B and Y-2C. Av e r a g e s c a l c u l a t e d FOR SIX TIDAL CYCLES BEGINNING THE MORNING OF 22 AUGUST, 1973.

F igure 13. Ax i a l c u r r e n t v e l o c i t y a v e r a g e s FOR CURRENT ARRAY LOCATIONS YV-2A, YV-2B a n d YV-2C. Av e r a g e s c a l c u l a t e d FOR SIX TIDAL CYCLES BEGINNING THE MORNING OF 27 AUGUST, 1973.

F igure 14. La t e r a l c u r r e n t v e l o c i t y a v e r a g e s FOR CURRENT ARRAY LOCATIONS Y-2A, Y-2B and Y-2C. Av e r a g e s c a l c u l a t e d FOR SIX TIDAL CYCLES BEGINNING THE MORNING OF 22 AUGUST, 1973.

F igure li>. La t e r a l c u r r e n t v e l o c i t y a v e r a g e s FOR CURRENT ARRAY LOCATIONS YV-2A, YV-2B and YV-2C. Av e r a g e s c a l c u l a t e d FOR SIX TIDAL CYCLES BEGINNING THE MORNING OF 27 AUGUST, 1973.

F igure 16. La t e r a l a n d a x i a l v e l o c i t y s , a v e r a g e d FOR TWENTY MINUTES, FOR CURRENT ARRAY Y-2B b e g i n n i n g 1026 EDST 22 Au g u s t , 1973 DEPTH IN METERS(m) 15- - 9 - 6 - 3 - 3 - 3 - 9 6_ - 9 02 UPSTREAM m SEC) (m //// / / y /> z - r v / DOWNSTREAM gr 12 Rgure s s s s s s s s s s s s 02 DEPTH IN METERS (m) - 3 - 3 YV-2C YV-2B YV-2A PTEM msc DOWNSTREAM (m/sec) UPSTREAM iue 13 Figure O.lO.t 02 DEPTH IN METERS(m) 12 r 9 6 9 6 0.2 - - - - LEFT (m/sec) 0 OKN UPSTREAM LOOKING iue 14 Figure RIGHT 0.1 0.2 DEPTH IN METER (m) 6 3 3 3 0.2 - - - - YV-2C YV-2A YV-2B ET , RIGHT , , LEFTq 0.1 (m/sec) a OKN UPSTREAM LOOKING iue 15 Figure 0.1 0.2 UPSTREAM (m / s e c ) DOWNSTREAM

Y-2B

OO C X l LU LjU

I— CL. L iJ Y-2B 3 ”

1 5 -

FIGURE 16 47

Wave Refraction

Wave celerity (velocity) is a function of the depth of

water through which the wave is propagating and the period of

the wave. Variations in celerity along a wave crest cause

the wave to bend toward shallow water. This bending can cause

the wave to focus its energy on a particular area, possibly

causing shore erosion.

A method of determining this focusing effect is to draw

wave orthogonals (lines perpendicular to the wave crests).

An assumption is made that the energy between two orthogonals,

sometimes called 'wave rays', remains constant (U. S. CERC,

1973) .

In early methods first suggested by O'Brien (1942) an

equation similar to Snell's Law for geometrical optics is used

to move the wave crest at a speed dependent upon the water depth

(the basic equation is Sine 0 / C = constant, where 0 is the angle

between a particular wave ray and an axis, and C is the wave

celerity). Orthogonals are then drawn on sets of wave crests

corresponding to advancing time. This method and other graphical methods developed later were extremely time consuming and required the use of a highly skilled draftsman.

With the advent of the high speed computer, methods were developed to numerically calculate wave refraction (these methods

still essentially use Snell's Law). Input information needed 48

by the computer models generally are accurate bathymetry and

wave input conditions such as period, height, and initial wave

direction.

In order to construct wave refraction diagrams for the

lower York River study area, two computer models were used, both

being supplied with depth information on two digitized grids,

each containing 3,7 50 depths taken from the bathymetric charts

York 1 and York 2, discussed earlier in this report.

The first model is a modified version of the Virginian

Sea Wave Climate Model (Goldsmith et a]L. , 1974) which incor porates a wave refraction program developed by Dobson (1967) .

This model analytically predicts refraction of waves generated outside of the study area. Figures 17-20 are refraction diagrams, with initial input periods of 2 and 3 seconds and initial wave directions for both the eastern and western portions of the study area being parallel to the river axis and into the study area (for the western section from 135°T and for the eastern section from 270°T).

The second model incorporates an extensively altered version of Dobson's model, developed by Goldsmith et ad.(1976).

This model, known as the Chesapeake Bay Wave Climate Model, uses as input, wind direction, velocity, and fetch, to generate a wave of a calculated height and period. As the wave moves down wind, the model periodicaly increases the wave height and period due to the increased fetch parallel to the wave direction.

These computations attempt to model locally generated sea 49

conditions. Figures 21-24 are refraction diagrams using the

model of Goldsmith et al^. (1976) with input conditions of 10

and 25kts (5.0 and 12. 5m-sec“*^) with a fetch of 8nm (14.6km)

and 4nm (7.3km) for the western and eastern portions of the

study area. The wind directions (ie., initial direction of

waves) used are 135°T and 270°T respectively.

From comparison of past and recent topographic maps of

the area, zones of high shoreline erosion are flagged on each diagram by an arrow (CHt>). One particular area of interest

is the zone indicated by a hatched arrow (Y 7 Z ^ > ) . This zone was the only location in the study area that had been noted as having severe erosion by Marcellus and Wass (1972) in their

study of the Gloucester County coastal zone. On all refraction diagrams having periods of 3 or more seconds in the eastern

section there is a convergence of wave rays in this area of severe erosion.

Another use of the refraction diagram is the prediction of wave-induced longshore currents. Many equations for de termining the volume of sediment moved by a particular long shore current exist (Caldwell, 1956; Fairchild, 1966; Longuet-

Higgins, 1972; Galvin, 1973), but the differences in their results are large. To avoid confusion I have used a qualitative method of predicting longshore drift which, is essence, gives the direction, but not the quantity of material moved. The method uses the comparison of shoreline orthogonals and wave orthogonals along the shoreline. If the angle between the 50

shoreline and wave orthogonals is great, then the longshore current should be high in that zone, and the direction should be in the direction of the vector portion of the wave orthogonal parallel to the shoreline (Figure 25).

On figures 17-24 arrows are drawn along the shore to indicate the direction and relative strength of the wave- induced longshore current.

It was not within the scope of this study to produce wave refraction diagrams with initial wave directions other than parallel to the channel axis. This limitation is com pounded by the difficulty in constructing wave refraction diagrams in an area of high current velocity, which in itself can induce refraction (Wiegel, 1964, pp. 170-173). Nevertheless, wave refraction studies help with an understanding of the processes that are active in moving sedimentary material. 7Io LZ

k Li iVTo =0 ind W (Az=270°T, T=3, e f r a c t i o n R ave W FIGURE FIGURE Id. LOWER YORK RIVER ESTUARY—

TTcjZT 13kts/270°T)

ind (W e f r a c t i o n R ave W LOWER LOWER YORK RIVER ESTUARY— 21. 21. FIGURE FIGURE FIGURE 2 2 , LOWER YORK RIVER ESTUARY— Wave Refract ion (Wind 10kts/13E>°T) 37Q1A

37°14 25kts/135°T)

ind (W ion

efract R ave W

■>p. FIGURE FIGURE 24. LOWER YORK RIVER ESTUARY— 59

Figure 25. Method of determining direction and RELATIVE STRENGTH OF LONGSHORE CURRENT. FIGURE 25 FIELD METHODS

The field portion of this study consisted of two phases;

sediment sampling and analysis, and seismic profiling.

Se d i m e n t Sa m p l i n g a n d A n a l y s i s

During the spring and summer of 197 5, a total of 5 9 hoctom

sediment samples v?ere taken using a 12cm clam shell sampler at approximate1y 0.5km spacing across the estuary ana 1km spacing along the estuary axis. In the Pass the spacing was decreased, to approximately 10 0m. The sample was limited to the upper 5cm of sediment. Size analysis was carried out on a small sub-sample of each sediment sample. Each sub-sample was wet sieved at 62.5u to remove all particles of sand or greater size. The remaining silt and clay was separated using pipet analysis as described by Folk (1968, pp,34-43). In all cases a known amount of Calgon solution was used to prevent f loculat.3.on „ The dry Calgon weight was subtracted f rom each sample after it was dry weighed.

Appendix A gives the location, depth, percent sand, silt, and clay, and size class!f.ication for each of the analysed s a Tip les. I n a. d dit.io n t o t h e s a mp les taken d u r ing t h i s s t u cl y,

Appendix A lists samples taken in the study area by Haven (1966)

61 62

Se i s m i c Pr o f i l i n g

A sub-bottom survey of the study area was made during the

summer of 1974 using a Raytheon Model RTT 1000 Portable Survey

System which operates at a frequency of 7KHz and has a maximum

output of 2000 watts. The equipment was mounted on a 16ft

(4.88m) Boston Whaler.

Limitations of the survey system's performance were en countered in two areas of operation. Due to an automatic

switching component that prevents transducer 'ring' by open

ing the receiving circuit until the sound travels approximately

6m in water, no output was recorded in water less than 3m deep.

The survey was, therefore, limited to the channel and channel margins of the estuary. In some locations in the study area

(especially in the western section) no acceptable signal was received, due to the presence of a very strong 'multiple effect', indicating poor signal penetration. Later researchers

(Nichols and Thomson, 1975, Personal Communication) experienced a similar phenomenon in sub-bottom profiles of the James River, and found that the sediment contained high amounts of gas, which greatly hinders the effectiveness of seismic devices.

Na v i g a t i o n

Navigation for both sediment sampling and sub-bottom pro filing was achieved by means of simultaneous sextant angles on three known positions as described by Dunlap and Shufeldt

(1969) . BOTTOM SEDIMENTS AND PROCESSES

Ge n e r a l D e s c r i p t i o n

The main tidal channels and other deep portions of the lower York River bottom are covered by an homogeneous mass of black mud of varying thickness, interspersed with scattered streaks of grey mud. In most places in the channel, the mud is clayey-silt which changes to silty-clay in extremely deep locations. As the depth decreases on the terrace slope, the mud changes into sand-silt-clay or silty-sand. The sediment zone nearest the shore, and in general, limited to the terraces, is sand.

A total of 59 sediment samples, supplemented by four sets of samples from a previous study (Haven, 1966), were used in this investigation (Figure 26). A description of each sample is given in Appendix A.

Sa n d a n d La r g e r Pa r t i c l e s

Figure 27 is the weight-percentage distribution of sand and larger particles in the study area. The sand, consisting primarily of quartz and shell fragments, has a fairly regular distribution. The coarser sediments are usually found in the

63 64

shallowest water and become finer as the depth increases. In most cases the sand percentage decreases rapidly at a depth of 4-5m, which corresponds to the submerged-terrace edge.

At this point, the depths rapidly increase and the sand per centage becomes minimal.

Exceptions to this observation are sediment samples 53,

54, and 55, located in the southern portion of the Yorktown-

Gloucester Point Pass. These samples contained high percent ages of sand even though they were taken at depths of over 2 0m.

The Yorktown-Gloucester Point Pass is an area of high currents and contains an area (southern side) of steep bottom slope

(8 degrees). There appears to be little or no filling within the last 100 years in the area of samples 53-55 (see chapter of this report on fill and scour), which indicates that the current velocities must have been sufficient to remove most of the fine grained particles, or at least removed enough fine particles to balance that which was being deposited. Available current records are inadequate to determine if this situation exists during all tidal cycles or is the result of high river discharge during rainy periods.

One observation concerning two of the three samples discussed above (53 and 54) is the presence of cinders. Pre sumably these are the ramains of Naval Ship discharge during

World War I, a time when many coal-fired ships used the York

River as an anchorage. 65

S ilt

By far the dominant estuarine sediment is silt. Its dis tribution is shown in figure 28. The silt fraction tends to increase with depth, going from a minimum concentration of 1.8 percent at a depth of 1.5m (sample 43) to a maximum of 8 0.3 percent at a depth of 15.5m (sample 33). Deeper samples did not show any increase in silt content. In fact, the deepest sample taken (sample 54 at 34m) contained only 2.6 percent silt. This sample, discussed earlier, is in an area that is worked by high currents. The highest silt concentrations are found in those deep areas of the estuary where current veloci ties are relatively low.

Cl a y

Areas of high clay percentages (Figure 29) were found in the most extreme depths, with the exception of the southern area of the Yorktown-Gloucester Point Pass. The percentage distribution of clay sized particles increases as the depth increases. Very little clay is found on the terraces. In the

Pass, an interesting phenomenon exists. The sample with the least clay is sample 53, taken at a depth of 21.5m. The sample with the maximum amount of clay is sample 57, taken in 16.5m of water. Both samples (53 and 57) were taken on a range in the narrowest section of the Pass, and were less than 5 00m apart. This situation is anomalous. In all other sections, the clay percentage increases as the depth of water increases. 66

Ge n e r a l Bo t t o m Ty p e s

The general bottom type distribution (Figure 30) is based on the classification of Shepard and Moore (1955). To construct this bottom-type map, percentages of sand, silt and clay for each sample are plotted on a triangular graph, such as that shown in figure 31. The size nomenclature can be assigned to each sample depending on its position on the graph. Figure 30 was constructed by superimposing the sand, silt, and clay per centage isopleths and using the nomenclature of Shepard and

M oore.

The general distribution of bottom types changes from sand in the river margins and shallow submerged-terrace regions to clayey-silt as the depth increases. In extreme depths silty- clay is the dominant sediment. «£§'•• ?gJ a '.. . jar ■'tI lEEsfsiiffl Sediment Sample Locations Sample Sediment 2*0, FIG'uRE FIG'uRE

U... ^^..,«.MM*.,..^^..,,.^ ' ' Wm '' ;; V 1 U

> ffe/' ^\37°I5'

!;1 iV'ti FIGURE 29, D istribution of clay sized p a r t i c l e s . FIGURE 30, General Bottom Types ZCLAY

S T I, T Y - S A N I). S A N D

%SAND

FIGURE 31. SEDIMENT NOMENCLATURE GRAPH 73

F ill and Scour

Due to the nature of the flow patterns, estuarine rivers are often subject to high rates of sediment accumulation.

There are three possible sources for this sediment influx: land drainage, bank erosion, and influx from the sea (or in the case of the York, from the Chesapeake Bay).

Brown et: al. (1938) studied 'silting' in the York, but did not overlap the area covered by my study. They found a relative ly slow rate of accumulation between the years 1857 and 1911, followed by a high rate of accumulation between 1911 and 1938.

More recent data have not been recorded.

Water depths along five ranges across the estuary were compared for the years 18575, 19116, 19457 , 19528, and 19739, to provide a descriptive measure of the filling and scouring rates in the present study area. Locations of ranges used in this study (Figure 32) coincide with those used by the U. S.

Army Corps of Engineers (Footnote 9) for the Chesapeake Bay

Model study.

~^U. S. Coast Survey H583 6U. S. C&GS H3310 7U. S. C&GS H7022 8U. S. C&GS H7952 and H7953 9U. S. Corps of Engineers H-10-15-03(4)&(5) 76140' 76°l30 lO o o >

FIGURE 32. RANGES USED IN FILL AND SCOUR INVESTIGATION. 75

Transects Y1-Y5 are shown in figures 33-37, each containing

cross-sections for four hydrographic surveys between 1857 and

1973.

Transects Yl, Y2, and Y5 coincide with piers that regular

ly handle large ships and have been dredged in the past ten

years. Transect Yl contains an anomaly for the 18 57 cross-

section. It is possible that due to navigation errors the

channel data were shifted approximately 50m. There is no way

to verify the accuracy of that survey, except to note that the

terrace edge on the 18 57 cross-section does approximately coin

cide with that for later years, and may be interpreted as an

indication of accuracy for the whole cross-section.

The accuracy of this investigation is limited by the accu

racy of the original soundings. From information supplied by

Sallenger et al. (197 5) , the maximum permissible horizontal

error was calculated to be 11m, while the maximum permissible

vertical error was lm for 18 57 and ranged to approximately 0.3m

for 1973.

A plot of cross-sectional areas at mean low water on the

five ranges across the estuary (Figure 38) indicates that there was filling in all cases between the years 1857 and 1911. On

transects Yl, Y2, and Y4 there was scour between 1911 and 1952, while transects Y3 and Y5 had substantial accumulation of sed

iment. Between 1952 (1945 for Y5) and 1973 there was a general

scouring trend, although transect Y2 showed minor sediment accumu

lation. Man-made changes (dredging and ship propeller wash) can account for extensive scouring on transects Yl and Y5 during this period. CM LO GO

in co m *-i r* r- 00 0 ) 0 ) 0 )

Q Q O 0 1837-1973

urveys S Yl—

ransect T FIGURE FIGURE 33,

^ , 0 0 5.00 10.00 T¥ 7oo 20.00 nFPTN fMFTFRRl o. n» CM o IT o O)

LO QC CO o O

o o CO. CM 1837-1973,

urveys O o o CM. Y2— S

O O ransect O

60 . T

O r> O. O FIGURE 34

o 00 1 0 . 0 0 i l j . O O nCDTU fMC’TC.'DCk OJ in o> o CD. H CO ^ in to az in *-• 7# t*- o o c 00 0 ) 0 ) 0 ) o o

ID.

O 1857-1973.

O Surveys Y3—

O O CD.

CD Transect

O CD ^3 o iO FIGURE FIGURE 35.

CD o |

'b.oo 10,00 riKPTH iMFTFRS) o o

1 CM o LO o O) o o COJ cn r- ^ in co 0C in ^ =i» r- CD cn 00 0 ) 0 ) 0 ) o o m o o cnCM. > -

o o 1857-1973. Surveys Surveys Y4— Transect Transect FIGURE FIGURE 3b.

^b.OO 5.00 1 0 . 0 0 liToo 20.00 DEPTH (METERS) OJ in an

r - in co in —• =r r** c c co cn cn cn o

>— 0 O < V 1837-1973 Surveys Surveys Yb— 37. 37. Transect FIGURE FIGURE

10.00 lV.OO 20.00 DEPTH fMETERS) 81

Figure 38. Cross-sectional areas at mean low WATER (MLW) ON RANGES Y1-Y5 OF THE lower York River Estuary. The SOLID AREAS REPRESENT REMOVAL OF SEDIMENT WHILE THE HATCHED AREAS REPRESENT DEPOSITION. Deposition H I I ! II ITT

Re m o v a l CROSS-SECTIONAL AREAS AT MEAN LOW WATER METERS X K r 0 r 20 2 28 L\ ER F SURVEY OF YEAR IUE 38 FIGURE

1973 83

The width of all five transects has essentially remained constant for the survey years 1857 to 1973. This allows us to use the average depth of water^^ (Table 3) as an indicator of sediment accumulation or removal. The major area of activity

(Figure 39) is in transect Y3. In all other segments, the sed iment accumulation and removal appear to be of little consequence, and there is no trend of movement of the locus of deposition as noted by Brown et 3^1. (1938) for the upper reaches of the York.

In transect Y3 there has been minor scour on the south side of the transect and drastic filling on the north side (Figure 40).

This filling has been in excess of 6m. It is possible that an ebb-tide current eddy (Figure 41), which is often observed, allows material to come through the Pass, but traps it near the eastern side of Gloucester Point. This material, consisting mostly of sand and silt, is a possible source of sand for the beaches on the eastern side of the Point. The mechanism for transporting this sand to the beach and presumably back to the source remains unknown at this time.

■^Cross-sectional Area/Width TABLE 3 AVERAGE DEPTHS*(meters) ACROSS THE LOWER YORK RIVER ESTUARY TRANSECTS Y1-Y5

VO Yl I £ - Y3 . Y4 Y5 1857 6.74 7.29 12.62 6.25 4.39 1911 6.62 7.26 12.16 5.88 4.18

1945/1952 6.86 7.29 10.58 5.91 4.12 1973 6.95 7.26 10.70 6.13 4.57

*Cr o s s -s e c t i o n a l a r e a /Width 85

F igur e 39. Fill a n d s c o u r fo r t r a n s e c t s Y1-Y5. 1857 BATHYMETRY TAKEN AS ORIGIN. SCOUR im ) DEPOSITION 0.5— 2 0.5 1.5- — 0 . 1 . 0 — lY2 Yl - M / / / s I TRANSECTS • \ /• A 3Y Y5 Y4 Y3 \ w \ •A W • w \ 1973 1952 191 I ------87

Figure 40. 1 8 5 7 a n d 1 9 7 3 cross-sections of TRANSECT Y3.

F i l l -----

Sc o u r ---- WIDTH(m e t e r s ) D C D C O C CD CD D C D C ! N C D C D C D C D C NN O L O C l\ (saai3W)Hid3Q 'ST 0 0 6 ° 30 — 7 " ? - -- J < OlbiL V . n o 2 ^ r;-.(22! yV J >. s2

7TO _ . U 20 cn LU GO 13 I s——< C_J a p c5 au >■■--< PO PQ CO GO „_J UJ a p Q_ CO CO LU CO UJ LU Q cu

The stratigraphic sequence of deposits in the lower York

River Estuary was determined from seismic profiles (Figures

42 and 43), and Hack's (1957) analysis of the drilling records for the J. P. Coleman bridge spanning the Yorktown-Gloucester

Point Pass.

Contour maps of the top of the Tertiary material (Figures

44 and 4 5), sand and gravel isopach maps (Figures 46 and 47), and Holocene mud isopach maps (Figures 4 8 and 49) were con structed .

Due to the limitations in the seismic records discussed earlier, the maps of the western section (Figures 44, 46, and

48) are incomplete, while an acceptable record was obtained for the eastern section (Figures 45, 47, and 49).

The remnants of four ancient channel thalwegs incising the Tertiary material (Figure 4 5) can be seen. The western most thalweg is slightly north of the present thalweg and is approximately at the same depth. Further downriver the pre sent channel occupies the ancestral channel (the eastern most thalweg) and is on the order of 4m shallower. The northern and southern thalweg appears to be a relic meander or alternate

90 91

channel of the main channel and is not within proximity of

any present drainage system of any significance. The northern

ancient thalweg possibly was associated with the ancestral

Sarah Creek drainage system which is located to the north of

the thalweg.

Presumably, these apparent thalwegs in the Tertiary

material represent Pleistocene channelization of the York.

Without datable material from just above the Tertiary contact,

the exact age of these channels is unobtainable. It is reason

able to assume that they were formed during one of the last

three Pleistocene glacial advances (Illinoian, Altonian or

Woodfordian), because sea level during the Nebraskan and Kansan

appears to have been above the present level (Fairbridge, 1960).

However, a channel formed during the Illinoian or Altonian may

have been rescoured during the last glacial advance, the Wood

fordian, and therefore, be covered with material of recent age.

Contour maps of the top of the Tertiary facies indicate that

the estuarine channels of recent time generally correspond to

the location of channels formed during the Pleistocene.

Pleistocene sand and gravels (Figures 46 and 47) up to

10m thick appear to line the bottom of the ancient main channel

and the southern ancient channel, while Holocene muds (Figures

48 and 49), ranging in thickness from 2 to 12m, cover all regions

other than the submerged-terraces, filling ancient channels and

smoothing out Pleistocene topographic highs and lows. This

results in a smooth sloping surface which gives no indication of the variations in the thickness of the muds below it. 92

In the event of another glacial advance accompanied by

a lowering of sea level, the areas of thick mud deposits will be the areas most easily eroded, and thus, will become the

future non-estuarine channels of the York River.

A generalized stratigraphic sequence of sediments in the York is given in Figure 50.

W&ikSMW m m l m :

j M M B K M k J Bh^jS^SSj 5 *^*^Sf!‘: ih fflSfSflmm 1 1 m |^Bpymfcy?x- '.-i^BKi

..;; j:;‘- FIGURE 4b. TOP OF THE TERTIARY FACIES— LOWER YORK RIVER ESTUARY (e a s t )

FIGURE 47. SAND AND GRAVEL ISOPACH MAP— LOWER YORK RIVER ESTUARY (east). (west),

i"M- HOLOCENE HUD HAP— ISOPACH YORK LOWER RIVER ESTUARY i, FIGURE FIGURE 4c 37°I4‘ (east). FIGURE FIGURE HU. HOLOCENE HUD HAP— ISOPACH YORK LOWER RIVER ESTUARY frloZ£ AYS o j

6 LACIAL AND GRAY’ (FI IJVIAI POSSIRLY DEPOSITS MUDS

nn ed SAND GRAYS

UPPER SANDY BEDS YORKTOWN CONTATN1NG FORMATI Of MANY FOSS I

INTER] OWER FOSS11 I—! ORKTOWN SANDS AN!) ORMATIOf SANDS

FIGURE 50. STRATIGRAPHIC SEQUENCE OF SEDIMENTS BELOW YORK RIVER ESTUARY BED. DISCUSSION AND CONCLUSION

Evidence suggests that the location and direction of the present York River Estuary is primarily a function of the thalweg and flood plain of the glacial-Pleistocene York River.

During the Illinoian glacial advance, sea level fell below -75m (Fairbridge, 1960), probably causing the flow in what is now the York River Estuary to be unidirectional, flow ing southeast and following the regional dip. Seismic evidence demonstrates that the ancestral York turned to the east near the present Yorktown-Gloucester Point Pass as does the present estuary. If the ancestral York had continued to the southeast it would have had to incise Tertiary deposits to the south of the present location. An extensive survey by Johnson (197 2)

(Figure 51) shows that this is not the case. This same survey demonstrates that the paleotopography of the Tertiary material, the 'basement' material for the Lower York System, dips south easterly until it reaches the Pass region, then the dip changes to the east. This dip change appears to be the cause of the change in direction of the York.

Although, there are submerged meanders evident in the present bathymetry (Charts YORK 1 and YORK 2), there is no evidence to suggest that the ancestral York departed from its present boundaries. The present straightness upstream of the

Pass is a function of the flooded river-valley topography.

102 C n J

O')

^ _ O CO~ jr . c:

s.: o o Crl U. 51. 51. Paleotopography on top the of Yorktown Formation (Tertiary).

1 FIGURE FIGURE 104

A recent exposure of Tertiary material on the eastern

shore of Gloucester Point indicates that the Pass existed

during the Illinoian. During the Sangamon interglacial age,

sea level rose to approximately +14m. Fluvial and estuarine

clayey-sand was deposited on much of the land mass in the study

area (Norfolk Formation).

Following the Sangamon, the Wisconsin glacial advances

(Altonian and Woodfordian) caused sea level to fall to approxi mately -100m. The York again developed a unidirectional flow,

allowing the water to cut deep into sediments deposited during the Sangamon and in some places into the Tertiary material below the Sangamon deposits. There is no evidence to suggest that the river meandered out of its present boundary during the Wisconsin.

Approximately 18,000 years BP sea level began to rise quickly. This rise slowed down 3-6 thousand years BP. Formation of the broad submerged terraces, which are common in all of the estuaries of the Chesapeake, could be the result of the in creased time that wave energy has had to erode the banks (Rosen,

1976) .

As the sea rose to approximately -20m, salt water began to intrude into the lower York, causing the circulation to change from unidirectional to the bidirectional flow (Figures

12-15) presently found in the estuarine Chesapeake System. 105

Sedimentation in the York appears to be primarily a func

tion of river hydraulics which is, in itself, a function of sea

level, tidal forces, and water density differences between the

fresh water and salt water bodies. During times of low sea

level (lower than -2 0m) flow is unidirectional and probably

turbulent. Fine material is left in suspension and eventually

deposited on the flood plain during times of flooding or it is

completely removed from the system with the water that carries

it. What remains are sands and gravels, their distribution de

pending on the amount of turbulence and sediment supply. The

distribution of sand and gravel, as indicated by the seismic

survey and Hack's (1957) analysis of drill logs at the Pass,

indicate that the distribution of these coarser materials is

widespread.

Sea level positions higher than -20m cause the circulation

patterns to be drastically different than those at lower levels.

A bidirectional flow system is established, with the average

bottom velocities being upstream. This low upstream velocity

allows fine material to be deposited by settling or floculation.

The deposition of fine materials is often enhanced by biodepo

sition. Benthic organisms, such as the oyster and clam, can deposit fine material as fecal pellets at a significant rate

(Kraeuter and Haven, 197 0; Haven and Morales-Alamo, 197 2).

The broad submerged terraces of the estuarine York are primarily covered with fine sands. This sandy character can be

attributed to high bottom orbital velocities of the locally generated wind waves. Clay and silt sized particles are more 1 0 6

easily suspended and so not fall back as quickly sis sand. The

clay and silt sized particles are kept in suspension until they

fall below the influence of the wind waves (depth approximately

3iu) .

The most interesting local feature is Gloucester Point,

which forms the Yorktown-Gloucester Point Pass. Gloucester

Point is similar to what Johnson (1919, p.322) called a 'cuspate

bar5, which is a recurved spit containing a marsh and is caused

primarily by waves and currents. Some of the material, found

near the tip of the Point is of Tertiary age, indicating that

the Point existed in some form during much of the Pleistocene.

The cuspate type sand-and-marsh spit appears to be a recent

development. From casual observation of groins on both sides

of the spit and wave refraction studies, it is concluded that

the predominant longshore drift is toward the Point on both

sides of the Point. Drift, plus a sediment supply from eroding

cliffs updrift on both sides of the Point, have casued the spit

to build out into the York. This channelward building appears

to be controlled by the high current velocities m the Pass.

As the spit builds out, the velocities increase until they are great enough to remove the material being deposited, or cause the material to bypass the Point. Material, being moved down- estuary by wave-driven longshore currents, may be moved past the

Point by high upper-layer ebb-tidal currents in the throat and deposited in the lower-velocity current zone to the east of the

Point. This is an area, noted earlier, of rapid deposition.

A similar argument is made to explain the presence of deep 107

areas along the thalweg to the east and northwest of the Pass.

What appear to be deep areas may, in fact, be the result of dep osition in the areas around them. Two pronounced 'shoals' are found in the areas where the estuary widens (and, therefore, current velocities decrease). It is possible that some material remaining in suspension in the pass settles out due to these lower velocities, causing the formation of shoals or 'deltas'.

Va r i a b l e s Ef f e c t i n g Mo r p h o l o g y

From the above discussion it can be seen that the major factor controlling the estuarine period of a river is sea level.»

If the level is extremely high, as was the case during the Sang amon interglacial age, the land masses forming the river valley will be submerged and the river will exist as a remnant channel

(if any bathymetric indication remains). During times of low sea level this same area would be strictly fluvial, its mor phology being determined by those variables given by Shumm (1972, p. 376) (Table 1).

I suggest that a fourth time scale, 'estuarine', be added to Shumm's table and have a length of the order of 10^ years, that period of time that a particular section of a river is estuarine (Table 4).

Variables added to Shumm's table would be: sea level position and rise (or fall) rate; tidal forces; salinity of the salt water body; wind waves and swell; and biologic activity (including man). TABLE A

RIVER VARIABLES DURING THE ESTUARINE TIME SPAN

Va r i a b l e s St a t u s o f Va r i a b l e

1. T i m e (s t a g e ) NR 2. Initial Relief NR 3. In i t i a l e s t u a r i n e r e l i e f I 4. Geology(lithology, structure) I b. Paleoclimate I b. Re li ef or v o l u m e of s y s t e m a b o v e BASELINE NR /. Va l l e y d i m e n s i o n s 5. Cl i m a t e D. V e g e t a t i o n 10. Cha nn el morphology 11. Ob s e r v e d Qw Qs (r e f l e c t i n g meteorological e v e n t s ) D 12. Hydrology(mean discharge of water a n d s e d i m e n t ) I 13. Hy d r a u l i c s o f f l o w X 14. Se a l e v e l p o s i t i o n a n d r i s e r a t e lb. T i d a l f o r c e s 16. Sa l i n i t y differences 17. W ind waves and ocean swell 18. B i o l o g i c a l a c t i v i t y (i n c l u d i n g m a n )

I = Independent

D = Dependent X = Indeterminate NR = Not Relevant SUMMARY

The general morphological character of the Lower York

River Estuary reflects the morphology of the ancestral glacial-Pleistocene York River. Changes in the sea level rise rate have allowed a general widening of the estuary, while changes in the flow characteristics, caused primarily by tidal processes and salt water intrusion, have caused muds to be deposited in most of the estuary. The post-

Pleistocene widening of the estuary has allowed wind waves to generate sufficient bottom velocities to cause the sub merged terraces to be covered with fine sand.

Tertiary deposits on Gloucester Point indicate that the

Point is of pre“Pleistocene origin. Wave generated longshore currents are the primary building force for the spit, creating the present Yorktown-Gloucester Point Pass, while current velocities control the amount of outward building of the spit.

Variables that affect estuarine rivers which are non- existant, minimal, or of dependent nature in fluvial rivers are: hydraulics of flow; sea level position and rate; tidal forces; salinity of the salt water body; wind waves and swell; and, biological activity (including man). It is proposed that a fourth time scale be added to Shumm’s (1967) ’river variables during different geologic time spans,” and be called 'estuarine1.

109 APPENDIX A

Sediment Samples

A1 Sa m p l e D e p t h (m ) La t ,(37°) Lo n g ,(76°) Sa n d % S i l t % Cl a y % Ty p e *

Y24 19.0 14 ' 0 1 " 2 9 ’42" 16.5 44.0 39.5 CSi

Y25 24.5 14 ' 15" 3 0 ’02" 21.8 37.1 41.1 SSiC

Y26 24.0 14 ' 2 0 " 3 0*13" 46.7 31.8 21.5 SSiC

Y27 2 2 . 0 14 ' 25 " 3 0’10" 6.3 58.8 39.9 CSi

Y28 1 2 . 0 14 ' 36" 3 0 ’05" 14.0 45.5 40.5 CSi

Y31 7.0 17 ' 30" 3 4 ’12" 23.2 31.3 45.5 SSiC

Y32 1 2 . 0 17 ' 24" 34'28" 8.3 45.9 45.8 CSi

Y33 15.5 17 ' 18" 34'4 5" 9 . 9 80.3 >9 .8 Si

Y34 7.5 16 ' 43" 33'58" 25.9 62.2 11.9 SSi

Y35 14.5 17 ’0 0 " 33'46" 29.7 35.6 34 .7 SSiC

Y36 2.5 17 ' 1 4 " 33 033" 22.5 46.4 31.1 SSiC

Y37 2.0 17'23" 33'27" SHELLS++++++++++++

Y38 8.0 16 * 13" 32'50" 77.6 12 .5 9.9 S

Y39 14.5 16 ' 45" 33'16" 16.5 44.7 38 .8 CSi

Y40 2.0 16 ' 08" 32'57" 96.9 1.9 1.2 S

Y41 13.0 16*30" 32’42" 4.3 54 .4 41.3 CSi

Y42 9.0 16 ' 41" 32’29" 4.3 50.3 45.4 CSi

Y43 1.5 16 '4 9” 32’22" 97.3 1.8 0.9 S

Y44 2.0 16 ’ 17" 31’48" SHELLS++++++++++++

Y45 14.5 16 1 02 32'04" 13 .7 36.4 49.9 SiC

Y46 9.5 15 ’52" 32'15 " 13.8 46.7 39.5 CSi

Y47 6.0 15'48" 32'21" 7.6 52.2 40.2 CSi . 21„ Y48 12.5 15 31'46" 15.6 45.4 39.0 CSi

*C-Clay Si-Silt S-Sand Sample Depth(m) Lat.(37°) Lo n g .(76°) Sa n d % Silt% Clay% Type*

Yl 10.5 13'37" 26 '4 9" 9 . 6 59 . 8 30.6 CSi

Y2 13. 0 13'48" 26 '49" 7.6 57.6 34.8 CSi

Y3 18. 0 14 '00" 26 '54" 1.3 69.3 29.4 CSi

Y 4 12. 0 14'10" 26 ''5 5" 0.8 63 .5 35.7 CSi

Y 5 6.0 14'30" 26 '58" 54.2 25.8 20.0 SiS

Y 6 2.5 14 5 46 " 26 '59" 88.6 6.7 4.7 S

Y7 2.0 14'46" 27 '15" 93.3 3.2 3.5 S

Y8 4.0 1 4 ’33" 27 113" 95.0 2 .1 2.9 c

Y9 9.0 14'22" 27 '21" 4.0 68.6 27.4 CSi

YlO 12.5 14'04" 27 '29" 2.4 69.4 28.2 CSi

Yll 14.5 13 ” 44 03 27 '41" 1.6 51.5 46.9 CSi

Y12 10.0 13'32" 27 '47" 2.1 65.9 32 .0 CSi

Y13 13.5 13'38" 28 147" 5.2 60.6 34.4 CSi

Y14 16.0 13'55" 28 '44" 3.7 50.0 46.3 CSi

Y15 10.5 14 ’ 1611 28 '39" 11.8 49.6 38 . 6 CSi

Y16 6.5 14'35" 28 '38" 47 . 0 27 . 0 26 . 0 SSiC

Y17 1.0 14'51" 28 '37" 95.7 2.0 2.3 S

Y18 1.5 1 4 ’55" 28 152" 88.0 6.5 5.5 S

Y19 2.0 14 ’46" 28 '58" 75.5 16 .2 8.3 S

Y20 6.5 14<35" 29 '04" 81.0 9.5 9.5 S

Y21 8.5 14'26" 29 '13" 9.9 59 .2 30.9 CSi

Y22 12.0 14'16 " 29 '19" 3.7 45.8 50.5 SiC

Y23 15.0 14'05" 29 '25" 2.3 39.1 58.6 SiC

*C-Clay Si-Silt S-Sand Sa m p l e D e p t h (m ) Lat.(37°) Long.(76°) Sa n d % SI LT% Cl a y % Ty p e '

Y4 9 13.0 15'37" 31' 30" 10.1 52.8 37 .1 CSi

Y50 6.0 15'47" 31'14" 25.0 39.8 35.2 SSiC

Y51 0.5 15*48" 30’54" 95.3 2.3 2.4 S

Y52 15.5 14'56" 30 '45" 1.8 43. 0 55.2 SiC

Y53 21.5 14'24" 30'35" 89.7 10.2 0.1 S

Y54 24.0 14'28" 30'32" 86.2 2.6 11.2 S

Y55 23.5 14'32 " 30 ' 27" 69.1 15.7 15 .2 Si S

Y56 18.5 14'36" 30 ' 25" 2.0 48 . 6 49.4 SiC

Y57 16.5 14'39" 30 ' 24" 0.8 39.6 59.6 SiC

Y58 15.5 14 '41" 30 ’22" 37 .2 40.3 22.5 SSiC

Y59 10. 0 14142" 30'21" 91.9 3.7 4.4 S

HI# 12.2 9.4 41.0 49.3 SiC

H2# 6.1 15 . 4 33.7 50.5 SiC

H3 # 3.0 88.4 3.9 7.7 S

H4# 1.5 93.4 2.2 4.5 S

Positions given by Haven (1966) as one mile east of the Yorktown-Gloucester Point Pass on the south shore and at the depth given.

*C-Clay Si-Silt S-Sand APPENDIX B

Su r v e y t o s u r v e y c r o s s -s e c t i o n comparisons f o r t r a n s e c t s Y1-Y5

B1 h* *h in ^ GO CT

*^.00 5.00 10.00 lF.OO 20.00 DEPTH (METERS) fM ID O)

^ IP DC O) O) D y —

x: o §— o CD o, O a*

o o *=* 10.00 15.00 20.00 ik.oo DEPTH CMETERSj CM o ITS o CD

IT CO cc t v o CD CD z DC O

o o

UJ 2TO

o o

O 40

5,00 10,00 00 DEPTH (METERS) C\J

o o e r3 o» o CO

^ , 0 0 5,00 00 L5.Q0 20,00 2^, 00 DEPTH {METERS) CM LO ay m i— ^ Lf) cn n c : >«—« ,-J4 o or 05 o> o

o —

o x: o i— o TD o o rj* CO

^ O O 5 . 0 0 10,00 15,00 20,00 0 0 DEPTH (METERS) o

OJ in CM o>

CO. CO in co r p r^ or O) O) o cu.

CO x:

10.00 lb. 00 20.00 5.00 DEPTH CMETERS) o o CO 9 O CO. CO r~ *-< cc in v-i o <30 O) o o 9 O CUJ CO BO

O 9 O CD. CM

£3 O -• O 0cu-“ * -

o C / ) n (Ta. a j ™

t : o co

a o -• a . .CNi

G T o U J ™

X I— HD O iT>

^ Q O 5,00 &0,00 lFToO DEPTH (METERS) CM LO o CO cn in co r# r- or o> o> o

60. CM

*— CD. o — »—«

o CM.

O O 7 D O

00 i d .00 b.oo 2b, 00 ib.oo DEPTH (METERS) in — • co CD O) o

>— 0 ©

5.00 10.00 i¥7oo 20.00 2b. 00 DEPTH (METERS) o o. a z f

coCO. OCED

co 1911 19145/1952 o o CM. > - CO O <1

o o m o CD. CM

'Ti.OO id.oo !¥7oo DEPTH (METERS) o o

CM o LO a >

X CD I— CD cc CD O) O) z CO o

C \ l a CD

X I— X E> CO

00 10.00 I F T o o DEPTH (METERS) r- *—i to ^ CO oo co o > -

' t . o o 10.00 l¥ .0 0 20.00 00 DEPTH (METERS) C\J 03in

in QZ 03 O) D >—

'ft. 00 5.00 10.00 7 F .0 0 20.00 DEPTH (METERS1 OJ in o LO co

CD. h“ CD LO CO az zf r- CD CD 05 z o

CD. CM

O O

O O O CM

O O

DC H o ZD

o 5.00 10.00 lb. 00 nFPTH fMFTFRSl BIBLIOGRAPHY

Anhert, F. 196 0. Estuarine meanders of the Chesapeake Bay area. Geographic Review 50(3):390-401.

American Geological Institute. 1974. Dictionary of Geological Terms. Anchor Books: Garden City, New York.

Baker, B. B ., Jr., W. R. Deebel, and R. D. Geisenderfer (eds.). 1966. Glossary of Oceanographic Terms. U. S. Naval Oceanographic Office: Washington, D. C.

Bowden, K. F. 1967. Circulation and diffusion in Lauff, George H. (ed.). Estuaries. American Association for the Advancement of Science Publication 83:15-36.

Brown, E. B., L. M. Seavy and Gorden Rittenhouse. 1938. Advance report on an investigation of silting in the York River, Virginia. U. S. D. A. Soil Conservation Report 3437.

Caldwell, Joseph M. 1956. Wave action and sand movement near Anaheim Bay, California. U. S. Army, Corps of Engineers, Beach Erosion Board Technical Memorandum 68.

Clark, T. H., and C. W. Stearn. 1960. The geological evolution of North America: A regional approach to historical geology. The Ronald Press: New York.

Curray, Joseph R. 1960. Sediments and history of Holocene transgression, continental shelf, northwest Gulf of Mexico in Shepard, F. P. et a^L. (eds.) , Recent sediments, northwest Gulf of Mexico 1951-1958. American Association of Petroleum Geologists: 221-226.

Davis, W. M. 1899. The geographical cycle. Geographical Journal 14:481-504.

Dobson, R. S. 1967. Some applications of a digital computer to hydraulic engineering problems. Department of Civil Engineering, Stanford University Technical Report 80.

Dunlap, G. D. and H. H. Shufeldt. 19 69. Dutton's navigation and piloting. United States Naval Institute: Annapolis.

Ill Dyer, Keith R. 1973. Estuaries: A physical introduction. John Wiley & Sons: London.

Emery, K. 0. 1967. Estuaries and lagoons in relation to continental shelves in. Lauff, George H. (ed.). Estuaries. American Association for the Advancement of Science Publication 83:9-14.

Fairbridge, R. W. 1960. The changing level of the sea. Scientific American 202 (5) :70-79.

Fairchild, J. C. 1966. Correlation of littoral transport with wave climate along shores of New York and New Jersey. U. S. Coastal Engineering Research Center Technical Memorandum 18.

Folk, R. L. 1965. Petrology of sedimentary rocks. Hemphill's: Austin, Texas.

Funk & Wagnall's. 1962. Standard dictionary of the English language. Funk & Wagnall's: New York.

Galvin, C. J., Jr. 197 3. Longshore energy flux, longshore force, and longshore sediment transport. American Geo physical Union Transactions 54(4):334.

Gilbert, G. K. 1880. Geology of the Henry Mountains in Shumm, (ed.). 1972. River Morphology. Dowden, Hutchenson and Ross: Stroundsburg, Pennsylvania.

Goldsmith, Victor, W. D. Morris, R. J. Byrne and C. H. Whitlock. 1974. Wave climate model of the mid-Atlantic shelf and shoreline (Virginian Sea): model development, shelf geo morphology, and preliminary results. SRAMSOE No. 38, Virginia Institute of Marine Science: Gloucester Point, Virginia.

Goldsmith, Victor, P. S. Rosen, W. S. Richardson, and C. H. Sutton. 1976. Wave modeling in limited fetch basins: Making waves in the Chesapeake Bay. Geological Society of America Abstracts with programs 8(2)183.

Hack, J. T. 1957. Submerged river system of Chesapeake Bay. Geological Society of America Proceedings 68:817-830.

Haven, Dexter S. 1966. Concentration of suspended radioactive wastes into bottom sediments. Progress report for contract AT-(40-1) 2789 of the Virginia Institute of Marine Science: Gloucester Point, Virginia.

Haven, Dexter S. and R. Morales-Alamo. 1972. Biodeposition as a factor in sedimentation of fine suspended solids in estuaries. Geological Society of America, Memoir 133: 121-130.

112 Hicks, Steacy, D., and James E. Crosby. 1974. Trends and variability of yearly mean sea level 1893-1972. National Oceanic and Atmospheric Administration Technical Memorandum 13.

Holdahl, S. R . , and N. L. Morrison. 1974. Regional Inves tigations of vertical crustal movements in the U. S., using precise relevelings and marograph data. Tectono- physics 23:373-390.

Jelgersma, S. and A. J. Pannekoek. 1960. Post glacial rise of sea level in the Netherlands ( a preliminary report ). Geol. en Mijnbouw 39 (6) :201-207.

Johnson, Douglas Wilson. 1919. Shore processes and shore line development. Hafner Publishing Company: New York.

Johnson, G. H. 196 9. Guidebook to the geology of the York- James Peninsula and south bank of the James River. Department of Geology, College of William and Mary in Virginia: Williamsburg, Virginia.

Johnson, G. H. 1972. Geology of the Yorktown, Poquoson West, and Poquoson East quadrangles, Virginia. Virginia Division of Mineral Resources, Report of Investigation 30.

Kraeuter, John and Dexter Haven. 1970. Fecal pellets of common invertebrates of lower York River and lower Chesapeake Bay, Virginia. Chesapeake Science 11(3):159-173.

Leopold, L. B., M. G. Wolman, and J. P. Miller. 1964. Fluvial processes in geomorphology. Wilt Freeman and Company: San Francisco.

Longuet-Higgins, M. S. 1972. Recent progress in the study of longshore currents ill Meyer, R. E. (ed.). Waves on beaches and resulting sediment transport. Academic Press: New York.

Mackin, J. H. 1948. Concept of the graded river. Geological Society of America, Bulletin 59:463-512.

Marcellus, Keneth and Marvin Wass. 197 2. Gloucester County coastal zone. SRAMSOE 26, Virginia Institute of Marine Science: Gloucester Point, Virginia.

Morisawa, Marie. 1968. Streams:Their dynamics and morphology. McGraw-Hill: New York.

O'Brien, M. P. 1942. A summary of the theory of oscillatory waves. U. S. Army, Corps of Engineers, Beach Erosion Board, Technical Report Number 2.

113 Pritchard, Donald W. 1955. Estuarine circulation patterns. American Society of Civil Engineers, Proceedings 81(717): 1- 1 1 .

Pritchard, Donald W. 1956. The dynamic structure of a coastal plain estuary. Journal of Marine Research 15: 33-42.

Pritchard, Donald XV. 1971. Chemical and physical oceanography of the Ch-sapeake Bay in Schubel, J. R. (Conv.). The estuarine environment-estuaries and estuarine sedimentation. AGI Short Course Notes IVA:l-28.

Rosen, P. S. 197 6. The morphology and processes of the Virginia Chesapeake Bay. PHd. Thesis, College of William and Mary in Virginia (in prep.).

Ryan, J. D. 1953. The sediments of the Chesapeake Bay. Maryland Department of Geology, Mines and Water Resources, Bulletin 12.

Sallenger, A. H., Jr., Victor Goldsmith, and C. H. Sutton. 197 5. Bathymetric Comparisons: A manual of methodology, error criteria and techniques. SRAMSOE 66, Virginia Institute of Marine Science: Gloucester Point, Virginia.

Shepard, Francis P. 1961. Sea level rise during the past 20,000 years. Contributions from the Scripps Institution of Oceanography, New Series 1297(31).

Shepard, Francis P. 197 3. Submarine geology. 3rd Ed. Harper and Row: New York.

Shepard, Francis P. and D. H. Moore. 1955. Central Texas coast sedimentation: characteristics of sedimentary en vironment, recent history and diagenesis. American Asso ciation of Petroleum Geologists, Bulletin 39 (8):1463-1593.

Shumm, S. A. 1972. Fluvial geomorphology, river mechanics in Shumm, S. A. (ed.). River morphology. Dowden, Hutchinson and Ross: Stroudsburg, Pennsylvania.

Stephen, L. W., C. W. Cooke, and W. Mansfield. 1932. Chesa peake Bay region. XIV International Geological Congress Guidebook 5.

Thornbury, W. D. 196 9. Principles of geomorphology. Wiley & Sons: New York.

U. S. Coastal Engineering Research Center. 197 3. Shore pro tection manual (3 vols.). U. S. Army, Corps of Engineers.

114 U. S. Department of the Interior, Geological Survey. 1974. Water Resources data for Virginia.

Virginia Department of Conservation, Division of Water Resources. 197 0. York River comprehensive water resources plan l(3):l-26.

Wiegel, Robert L. 1964. Oceanographical engineering. Prentis Hall; Englewood Cliffs, New Jersey.

115 VITA

MICHAEL JOSEPH CAiiHON

Born in Biloxi, Mississippi, March lL, 19^6. Graduated from Notre Dame High School, Biloxi, Mississippi,

June, 196^ and the United States Naval Academy, Annapolis, Maryland, June, 1968 (B.3. Oceanography). Commissioned as a Line Officer in the United States Navy, June, 1968, and served in Southeast Asia, Northern Europe, and the

Carribean.

Entered the School of Marine Science of the College of William and Mary in June, 197^* 37°I5‘ N 37°I5‘ [37,I4IN

YORK RIVER 2 (EAST)