~ - ~ 0 i ~ r ~ r l J LOANCOPY 0 CBCIII.Af>"u "9PN SeaCraot t|aposItory Depth-Area-Volume Relationshipsin NarragansettBay Richard A. Chinrnan Scott VV. Nixon GraduateSchool of Oceanography TheUniversity of RhodeIsland NOAA/Sea Grant Marine TechnicalReport 87 May 1985~ 'tNTlfl",I>I SF't I'R NT 0OE PO'.!TORY B~ i4PVb UR, lfif.iT, Ri 02tls. This publication is the result of researchsponsored by NOAA Office of SeaGrant, U,S, Department of Corn- merce, under Grant SNA81AA-D-00073. The U.S. Govern- ment is authorized to produce and distribute reprints for governmental purposesnotwithstandmg any copyright notation that may appear hereon. The cover figure <sa three-dimensional view of Narragan- sett Bay. Rhode Island, with transect I I as the southern Addttional copiesof this publication are available at S5 per border cseeFigure 10!. The land surface ts shown in dark copy from Publications Unit. Marine Advisory Service, The green, with the bottom topography in blue The computer- University of RhodeIsland, Narragansett. RI 02882-1197. generatedfigure was drawn using the G3D procedurein Order No. P1005,Please tnake checkspayable to The SAS!GRAPH. University of Rhode Island. CONTENTS 3 Introduction 58 18d. HypsographicCurve for the Fox Po t R 59 18e, HypsographicCurve for the SahmPoint Rm } 4 lvfethods and Procedures 60 18f, HypsographicCurve for the Nyatt Point R h A. Overview 61 19a, Cumulative Volume of thc Comhmcd S k k B, Digitization and Providence Rivers Below Pawtucket C. Transformation 62 19b. Cumulative Volume of the Scekonk River Be}ow D. Conversion Pawtucket E. Modifications for a More Detailed Analysis 63 19c. Cumulat!ve Volume of the Providence River of the Seekonk and Providencc Rivers Bc}ow Fox Pomt 8 Results 64 References List of Tables 4 1. Hydrographic Survey H!story List of Figures 5 2. Tide RangesBased on a Ten-YearNumerical Mode} {or Newport, R.I. 6 1. Narragansett Bay Elementsand Segments 5 3, Comparison of the Resultsof This Study with au 6 2. Idealized Cross-Sectionof Bay Showing Hypso- Earlier HypsographrcAnalysis by Hicks959! graphic Components 16 4. Summaryof thc Total Area and Volume, Mean 7 3. Detailed Seekonk and Providence River Elements Depth, and Shoreline Length and Segments 17 5. Estimated Volume of Water Present in Each Element 9 4. Bristol Harbor Contour Maps of the Bay Under Various Tide Conditions 10-15 5a-f, NarragansettBay Contour Maps l9 6a. Area and Volume of the Bay. Including Mount 18 6a. HypsographicCurve for theBay, Including Mount Hope Bayand the SakonnetRiver Hope Bayand the SakonnetRrver 21 6b. Area and Volumeof the Bay, ExcludingMount 20 6b. HypsographicCurve for theBay, Excluding HopeBay and the SakonnetRiver MountHope Bay and the SakonnetRiver 23 6c. Area and Volume of the West Passage 22 6c. HypsographicCurve for the WestPassage 25 6d. Area and Volume of the East Passage 24 6d, HypsographicCurve for theEast Passage 26 7a. Area and Volume of the Prov!dence River iCoarse 26 7a. HypsographicCurve for the ProvidenceRiver Grid Analysis! 27 7b. HypsographrcCurve for theUpper Bay 27 7b. Area and Volume of the Upper Bay 28 7c. HypsographicCurve for Greenwich Bay 28 7c. Area a.nd Volume o{ Grccnwich Bay 29 7d. HypsographicCurve for theUpper West Passage 29 7d. Area and Volume of the Upper West Passage 30 Sa. HypsographicCurve for the Lower West Passage 31 Sa. Area and Volume of the Lower West Passage 32 Sb, HypsographicCurve {ot thc UpperEast Passage 33 Sb. Area and Volumeof the Upper East Passage 34 8c. HypsographicCurve for theMiddle EastPassage 35 8c. Area and Volumeof the Middle East Passage 36 Sd. HypsographicCurve {or theLower East Passage 37 8d. Area and Volume o{ thc Lower East Passage 38 9a. HypsographicCurve for Mount Hope Bay 39 9a. Area and Volume o{ Mount Hope Bay 40 9b. HypsographicCurve for theSakonnct River 41 9b. Area and Volume of the Sakonnet River 42 10. NarragansettBay Cross-Sections and Bathymetric 52 10a. Volume and Cross-Sectional Area of the Provi- Prof}}cs denceRiver, Upper Bay,Greenwich Bay, and the 43 11. Cross-Sections Across Whole Bay West Passage 44 12, Cross-SectionsAcross Mouth of Bay 53 10b. Volume and Cross-Sectional Area of the Provi- 45 13, Cross-SectionsSeparating East and WestPassages denceRiver, Upper Bay.and the EastPassage 46 14, Cross-Sections Across the Mouths of the Provi- 54 10c. Volume and Cross-SectionalArea of Mount Hope denceRrver. Greenwich Bay. and MountHope Bay Bay and the Sakonnet River 47 15. Cross-SectionsAcross the Providence River and 55 1 la, Area and Volume of the Combined Providencc Mount Hope Bay and Scekonk Rivers 48 16. BathymetricProfiles AlongMajor Passages 56 lib. Area and Volume of the Scekonk River 49 17a. Cumulative Percent of the Total Volume of the 57 1 lc. Area and Volume of the Providcncc River Bay,Excluding lvfount Hope Bay and the !Detailed Analysis! Sakonnet River 58 lid. The Area and Volume of the Fox Point Reach 50 17b. Cumulative Percent of the Total Volume of the 59 lie. Area and Volume of the Sabin Point Reach ProvidenceRiver, UpperBay. and WestPassage 60 llf, Area and Volume of the Nyatt Point Reach 51 17c, Cumulative Percent of the Total Volume of the 61 12a Volume and Cmse-SectionalArea of the Comb}ned ProvidenceRiver, Upper Bay, and East Passage Provrdcncc and Scekonk Rivers 55 18a. HypsographicCurve {or the CombinedProvi- 62 12b. Volume and Cross-Sectional Area of the Seekonk dence and Scckonk Rivers River 56 18b. HypsographicCurve for the Scckonk River 63 12c. Volurnc and Cross-Sect}onalArea of the Provi- 57 18c. HypsographicCurve for the ProvidenceRiver denc,e River INTRODUCTION ln spite of the fact that Narragansett Bay is among sageby a line from Beavertail Point on a headingot the most frequently studied bodies of coastal marine 284" true to a small unidentified point on the shore water in the world. no detailed hypsographicanalysis of Boston Neck, about halfway between Bonnet Point of the system has yet been published, As part of his and the Narrow River inlet. description of the basic physical oceanographyof the ln a more detailed analysis of the Seekonk River area, SteacyD. Hicks 959! provided a depth-area- and the ProvidenceRiver !Figure 3!. the northern volurne curve for the bay as a whole. but the increas- hmit of the Seekonk is set at the Blackstone River ing intensityof researchand management efforts in- darn at Pawtucket and its southern limit is fixed at volving the bay requiresa more detailed and the Rt. I-195 highway bridge, The ProvidenceRiver extensive treatment. extends from that bridge to a line connecting Nayatt The lack of a hypsographicatlas is a common hand- Point and Conimicut Point. icap for those studying bays, lagoons, and estuaries There is no well-established definition of the bound- around the world, though it may come as a surprise ariesof Narragansett Bay iPilson, 1985!. and it is to those in social sciencesand managementthat such likelythat some will find good reasonto take excep- basic physical informationis absent or inadequate tion to those we have used here, Some of our deci- !Capper, Power,and Shivers, 1983!.The reasonfor sions were arbitrary:others were influenced by the deficiency is that the compilation of hypsographic geography or engineering. information by traditional interpolation and plani- metry is extremelytedious. However,it is possibleto bring togethercertain of the computermapping and graphics programspresently available to develop a relatively simple, rapid. highly flexible, and inexpen- sive analysisof bathymetric or topographicdata. This publication reportsthe resultsof suchan anal- ysis for NarragansettBay, includingbathymetric con- tour charts, the area, volume, incan depth, and shorebnelength for varioussubregions of the bay, cross-sectionalareas in a numberof placesalong the bay, the bathymetncprofiles of transectsalong the passagesof the bay, and the cumulativevolume of the bay as a functionof increasingdistance from various points.After a descriptionof the methods used in the analysis,the results are grouped in the order just describedand presentedin graphicaland tabular form. Although the boundarieswe havechosen for Nar- ragansettBay are shown in Figure1, it maybe helpful to provide a narrativedescription as well. The north- ern lunit is takenas the Rt. I-195 bridgeacross the combined Woonasquatucket-MoshassuckRivers and across the Seekonk River. The Providence River ex- tends into the Pawtuxet River on the west as far as the first dam. The Warren Riveris includedup to the Rt. 103 bridge. In Mount Hope Bay, th» Kickamuit Riveris taken asextending up to LaurelPark, the embaymentsof the Cole and Lee Riversup to their respectivebarrier spits and beaches,and the Taunton River up to the Rt. I-195 bridge,The SakonnetRiver extends from the Hummocks to a line from Sakonnet Point to Sachuest Point, The seaward limit of the East Passageof NarragansettBay is defined by a line from Brenton Point to Beavertail Point, and the West Pas- METHODS AND PROCEDURES Since there is tidal variation around MLW. a ta.ble A. Overview of tidal rangesis providedin Table2. Whentnulti- Thetechnique for derivinga computer-generatedpltedby bayarea, these values give an estimate of hypsographicanalysis of Narragansett Bayinvolved watervolume changes through a meantide cycle seeTable 5!. We havealso provided a tablethat three major steps: comparesa portion of theHicks hypsographic 1. digitizationof the locationsand depths analysis959! to our resultsIsec Table 3!. W'edo associatedwith publishedU.S. National Ocean this not to makeany claims as to the correctvalues. Survey