Full ecoregional plan - Conservation Gateway

Although the five EDUs had been previously qualitatively derived by TNC Freshwater Initiativestaff in 1999-2000, this analysis developed more quantitative descriptions of the physical settingand fish and mussel biota of the Ecological Drainage Units as follows:Physical DescriptionsTable 1: Physical Descriptions of Ecological Drainage UnitsEDU: Total Areaand river length byriver size classI. Cape Cod1160 sq.mi.Rivers:Size 2 = 86 mi.Size 1 = 916 mi.II. Saco –Merrimack –Charles9750 sq.mi.Rivers:Size 4 = 345 mi.Size 3 =695 mi.Size 2 =1603 mi.Size 1 = 12295 mi.III. LowerConnecticut9190 sq.mi.Rivers:Size4 = 338 mi.Size 3 = 570 mi.Size 2 = 1358 mi.Size 1 = 11546 mi.RiversIncludes Cape Codcoastal rivers directlydraining to the oceansuch as North, Sippican,Washpee, Quaeshunt,Slogums, West Port,along with manysmaller coastaltributaries andintermittent streams.Very large rivers (size4) include the Saco andMerrimack. Largeinland rivers draining tothe coast include thePresumpscot,Piscataqua-SalmonFalls, and Charles.Large inland riversdraining to theMerrimack include thePemigewasset,Contoocook,Piscataquog, Suncook,Nashua, andConcord. Largetributaries of the Sacoinclude the Ossipee andSwift. Medium sizedcoastal rivers drainingdirectly to the coastinclude the Neponset,Charles, Saugus,Ipswich, Parker, York,Mousam, Kennebunk,Little, and Royal.Very large rivers (size4) include theHousatonic,Connecticut, andThames, with theConnecticut being byfar the largest river.Large rivers draining tothe coast include thePawcatuck-Wood,Pawtuxet, Blackstone,and Taunton. Largerivers draining to thePhysical DescriptionLow elevation, very low gradient, acidic rivers primarily upon coarsegrained sediments. The elevation is entirely within the 0-800ft elevationzone, with the highest elevation being 377ft. Landforms are dominated bydry flats (64%) and wet/moist flats (19%). Bedrock is primarily acidicgranitic (46%) or recorded as extremely deep coarse grained sediment(47%). A small amount of acidic sed/metased and intermediategranitic/mafic bedrock exists. Surficial material is primarily coarse-grainedstratified sediments (73%) or till (13%) with small amount of fine-grainedsediment (6%) along the Taunton River. The EDU is 72% natural landcover with 8% in agricultural use and 21% developed.This EDU includes a diversity of aquatic habitats from northernmountainous, high elevation, high gradient systems dominated by cliffs,steep side slopes, coves and confined channels to southern, low elevation,very low gradient, meandering marshy, coastal systems. These systemscross a variety of bedrock and surficial material leading streams to have avariety of acidic to calc-neutral chemistry and flashy to stable hydrologicregimes. The elevation ranges from 0m to 6200 ft. in the White Mountainsof New Hampshire. The vast majority of the EDU is within the 0-800 ft.zone (76%) and a moderate amount in the 800-1700 ft. zone (19%).Landforms are dominated by gently sloping flats (26%) and dry flats(27%), but include substantial amounts of sideslope/summit features(22%). Bedrock is primarily acidic granitic (50%) with large amounts ofacidic sed/metased (24%), and small amounts of mafic/intermediategranitic (7%). A moderate amount of calcareous material is found (4% verycalcareous, 15% moderately calcareous) with the calcareous materialconcentrated in local areas of the Nashua River and Saco River andcovering nearly all the lower sections of the Presumpscot, Merrimack, andcoastal rivers of the Piscataqua-Salmon Falls watershed. Surficial materialis primarily till (47%), with moderate amounts of coarse-grained stratifiedsediments (22%) and patchy quaternary (19%), small amount of finegrainedsediment (9%). The patchy material occurs in the higher elevationmountainous areas of New Hampshire and Maine. The coarse-grained andfine-grained deposits are found primarily along the courses of the mediumto larger rivers, with an additional large area of fine-grained sediment ofmarine clay origin near the coast in the Presumpscot, Saco, and Piscataqua-Salmon Falls Watersheds. The EDU is 81% natural land cover with 8% inagricultural use and 12% developed.Primarily acidic, low elevation, low to very low gradient rivers, with only afew medium gradient headwater systems. The Housatonic watershedcontains substantial areas of calcareous bedrock influence. The vastmajority of the EDU falls within the 0-800 ft. zone (76%) and a moderateamount in the 800-1700 ft. zone (22%). The elevation ranges from 0m toover 2605ft in the Berkshire/Taconic mountains in Massachusetts.Landforms are dominated by dry flats (39%), and gently sloping flats(25%), with some sideslopes/summits (13%). (Bedrock is primarily acidicsed/metased (48%) with significant amounts of acidic granitic (26%) andmafic/intermediate granitic (16%). A small amount of calcareous materialoccurs (5% very calcareous sed/metased, 5% moderately calcareoussed/metased), concentrated in the Upper Housatonic and the Shebaug.Surficial material is primarily till (71%), with a moderate amount of coarseREVISED 6/2003AQUA-RESULTS-3