Abstract: Coverage lk_ws_all2 is a revised version of lk_ws_all with corrections to the lake and/or watershed borders for ME006L, ME266L, ME267L, ME506L, ME520L, NH253L, NY520L, NY522L, NY533L, NY766L, AND NY778L. Only the affected features and attributes were changed. This coverage contains polygons and labels for Northeastern lakes, islands, and watersheds included in the US EPA EMAP-SW sampling effort from 1991-1994. The watershed boundaries were delineated and digitized on a yearly basis by contractors at the EPA facilities in Corvallis, Oregon and Reston, Virginia . ARC/INFO was used for all GIS processes. U.S.G.S. topographic maps ranging from 1:24,000- to 1:250,000-scale were source materials. In general, when more than 6 large-scale maps were needed to delineate a watershed, the next smaller available scale was used. All boundaries were visually checked before and after digitizing. Items were added to relate watersheds to lakes and islands (if present) and watersheds "nested" in other watersheds. The yearly coverages were later joined into a single coverage, sliver polygons removed using DISSOLVE (nokeepedge option, edited, and items amended as needed. Also, lake and watershed areas were recalculated using an in-house program. Watersheds with more than 5% increase or decrease in AREA_WS were edited using ARCEDIT and the program run again. The major drainage basin name and hydrologic unit code was identified for each watershed by intersecting the polygon centroid with the U.S.G.S. Hydrologic unit map (1:250,000 HUC). Purpose: The purpose of the boundary coverage is to provide spatial reference for field and mapped data of sampled lakes and watersheds as well as the distribution of all 363 sites across the Northeastern United States. Data from the EMAP-SW lakes database can be related to the watershed boundaries using the item "LAKE_ID". Four lakes were assigned two different lake_id values in multiple years of sampling. In the boundary coverage, these are identified by the first year lake_id and any alternate identifier is noted in the "COMMENT1" field as an "AKA" (Also Known As). The coverage can be used to create maps and perform spatial analyses at a watershed or landscape level. However, watershed delineation accuracy and generalization varies due to the multiple map scales used. It was also edited by hand (on-screen digitizing) to correct errors in watershed area caused by the overlay process. Thus it is not recommended for detailed studies requiring high accuracy. Each intended use should be carefully evaluated. To reselect individual watersheds or lakes, use the codes as illustrated in the "NOTES" below. Limitations_of_Data: USE AT OWN RISK. Although the data has been reviewed, errors may still exist. The 1994 New England watersheds were delineated and digitized by an outside contractor. Work was reviewed by the Corvallis staff but only delineation discrepancies causing more than ~ 10% change in area or markedly different land use percentages were redigitized. Some lake and watershed boundaries were updated in 1998 when it was discovered that "field" and "office" versions of some lakes differed. The "office" maps were changed to match the "field" versions. Please inform GIS personnel if other significant errors are found. Entity_and_Attribute_Overview: For additional information see "NOTES" below. The coverages .PAT contains the ARC/INFO required items (AREA, PERIMETER, COV#, COV-ID) plus the following: FEATURE - "ISL" = island within lake "LK" = sampled lake "lk2" = second lake basin (ie. water pumped into sampled lake or connected to it) "WS" = watershed "WETL" = wetland area within or on perimeter of lake. LAKE_ID - unique indentification code. The first two characters identify the state (ie. NY= New York ) the next three digits are the site number, the last character is the single letter L for lake project YEARORIG - year of initial selection for particular sampling type (related to STUDY) STUDY - "EMAP" regular grid site "TIME" - augmented grid density for acid precip. analyses focusing mainly on chemistry "INDIC" - Hand-selected sites for testing multiple metrics and indicators during pilot phase LK-HA - lake surface area digitized from maps [excludes area of island(s) which are a part of "AREA_WS"] AREA_WS - watershed area (excludes sampled lake area) HUC - Major drainage basin code from USGS Hydrologic Unit Map (1:250,000), intersected with watershed centroid. CU-NAME - Major drainage basin name from USGS Hydrologic Unit Map (1:250,000), intersected with watershed centroid. WSLKCODE - A unique number for each lake and watershed polygon. This number is for the "minimum unit" for nested situations. Islands and watersheds have the same codes. Sampled lake wslkcode = watershed wslkcode + 100 WS_CODE3 - Identifies the second "middle" watershed in nested watershed sequence. Watershed is "nested in" two downstream watersheds AND has at least 1 watershed "nested" upstream. WS_CODE2 - Identifies the first "middle" watershed in nested watershed sequence. Watershed is both "nested in" one downstream watershed AND has at least 1 watershed "nested" upstream. WS_CODE1 - Identifies most downstream watershed of nested sequence. For a "stand-alone" watershed polygon (non- nested), all codes are alike ( wslkcode = ws_code3 = ws_code2 = ws_code1). For the lake polygon, wslkcode = ws_code1 + 100 and all ws_codes are equal. MIDWS - "0" = polygon is not part of any "middle" watershed in nested sequence. - "1" = polygon is a part of a "middle" watershed. NSTCODE - "0" = not nested in any other watershed "1" = nested in one other watershed, identified by the ws_code1 number "2" = double nested in 2 downstream watersheds which are identified by the ws_code2 and ws_code1 numbers "3" = triple nested in 3 downstream watersheds which are identified by the ws_code3, ws_code2, and ws_code1 numbers NESTEDWS1 - lists the lake_id of any watersheds nested within the selected watershed polygon, each separated with "/". (ex. ME002L/ME511L). For watersheds without nesting, "XXXXX" is inserted. NESTEDWS2 - continued list of lake_ids for watersheds nested within the selected watershed polygon, each separated with "/". (ex. ME002L/ME511L). For watersheds without nesting, "XXXXX" is inserted. NESTEDWS3 - continued list of lake_ids for watersheds nested within the selected watershed polygon, each separated with "/". (ex. ME002L/ME511L). For watersheds without nesting, "XXXXX" is inserted. COMMENT1 - comments about the lake or watershed (ex. NESTED_IN_ME526L; AKA_ME761L_1994_EMAP; LAKE_SIZE_DECREASING). Multiple comments are separated with "/" ; no comment = "XXXXX" Procedures_Used: 1) Delineated watersheds on topographic maps. 2) 2nd person checked delineation. 3) Digitized maps into appropriate UTM zone. RMS error generally <.005 for 1:24,000 or 1:62,500-scale maps in good condition, and <.010 for similar maps at 1:100,000 or 1:250,000-scale. In rare cases, RMS < .015 was accepted for maps in very poor condition and could not be sufficiently smoothed by ironing with low, dry heat. Map corners (NAD27) used for tics . 4) Added labels and LAKE_ID 5) Checked digitizing on-screen and on paper plot. 6) Made changes where necessary, 2nd person inspected new plot. 7) After all individual watershed coverages have met in-house quality criteria, used append or mapjoin (ARC/INFO commands) to create coverage by UTM zone. 8) Projected UTM coverages into ALBERS and append or mapjoin again. 9) Edited coverage, especially bordering or nested watersheds that created sliver polygons 10) Add items of interest, calculated areas, entered codes. 11) Checked entries. 12) Documented for internal use. 13) Repeated 1-12 for lakes/watersheds of following years. 14) Made items for all years coverages indentical. 15) Adjusted WSLKCODE and WS_CODE(X) values to eliminate duplications. 16) Mapjoin. 17) Dissolve nokeepedge option. 18) ARCEDIT new coverage, especially bordering or nested watersheds. 19) Checked and corrected the codes as nessesary. 20) Recalculated LK-HA and AREA_WS items. 21) ARCEDIT again for watershed areas +/- 5% different from original 22) Recalculate AREA_WS again for revised watersheds. 23) Documented for external use. 24) Put on EPA webpage. 25) Revised some lake and watershed boundaries as well as LK-HA and AREA_WS values, as needed. 26) Put new version LK_WS_ALL2 on EPA webpage. Revisions: This coverage is based on coverages compiled for each sampling year but has been revised extensively with added, renamed, redefined, or expanded variables. Although the item names "LK-HA" and "AREA_WS" are the same, the values were recalculated to reflect changes that occurred during the mapjoin, dissolve, or editing process. To resolve the redundancy in yearly min/mid/max codes, new codes were created by adding 1000, 2000, 3000, or 4000 to the codes in 1991, 1992, 1993, and 1994 grid coverages, respectively. Original codes (<1000) remained unchanged for the 1991 pilot "indicator" lakes. The new variables are now named wslkcode (formerly "mincode"), ws_code3 (no previous counterpart), ws_code2 (was "midcode"), and ws_code1 ("maxcode"). Also, the variable previously named "nestedws" has been expanded and renamed "nestedws1". New variables "nestedws2" and "nestedws3" were added to accomodate very long lists of nested watersheds. The "flag" or "com_strs" field is now called "comment". 10/98 Lake and/or watershed borders and appropriate attributes were changed for the following lakes: ME006L ME266L ME267L ME506L ME520L NH253L NY520L NY522L NY533L NY766L NY778L Reviews_Applied_to_Data: Informal reviews have been been performed by GIS staff and others at various stages. However, undetected errors may still exist. Please report. Related_Spatial_and_Tabular_Data_Sets: Refer to the EMAP-SW datasets for biolical, physical, chemical, and watershed stressor data related to these boundaries. The item "LAKE_ID" is common to all datasets. See also "reference" information below regarding the USGS Hydrologic Unit and topographic maps. References_Cited: U.S. Geological Survey, 1984, Topographic Instructions of the National Mapping Division, National Cartographic Information Center, Reston VA, 22092 Pete Steeves,1992, U.S. Hydrologic Unit Map, 1:25,000-scale, USGS Water Resources Division, MA. (508)-485-6360 Notes: This schematic diagram may help clarify the "nesting codes. ___________________________________________ | e | | | | | | | | | | d | <-- triple nested (uppermost) |_[E]__| | | [D]________| | | | c | <-- double nested (2nd "middle") | | [C]_________________| | | b | <-- nested (1st "middle") | [B]_________________________| | | | a | <-- downstream watershed [A]_______________________________________| Rectangular lakes [] "A,B,C,D,E" watersheds "b,c,d,e" nested in "a" watershed wslkcode ws_code3 ws_code2 ws_code1 midws nstcode a 11 11 11 11 0 0 b 12 12 12 11 1 1 c 13 13 12 11 1 2 d 14 13 12 11 1 3 e 15 15 15 11 0 1 lake [A] 111 11 11 11 0 0 [B] 112 12 12 11 1 1 [C] 113 13 12 11 1 2 [D] 114 13 12 11 1 3 [E] 115 15 15 11 0 1 ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: This is a section from an .aml that reslects the proper polygons for processing EACH watershed individually. /* /dsk/tiny2/cbj-emap/centroids.aml /*************************************************************** /* Produces a point coverage of the centroids for a set EMAP-SW /* watersheds. The program creates a polygon for each watershed, /* taking into acccount whether or not the watershed is nested /* in another watershed. Requires a file called wsall.lis which /* contains the following lk_ws_all.pat items for each watershed: /* wslkcode lake_id midws nstcode (Ex. 1000,"CT002L",0,0) /* G. Bishop 1/7/94, 3/9/94, 8/94 /* modified by Colleen Burch Johnson 7/94, 8/97 /* ARC 7.1.1 Sun sparcstation /*************************************************************** /* &echo &on &watch centroids.wat &sv dir /dsk/tiny2/cbj-emap/ &sv cov lk_ws_all /* &sv outcov lk_wscntrd /* &if [exists ./cent.lis -file] &then &sys rm ./cent.lis &if [exists ./id.lis -file] &then &sys rm ./id.lis &if [exists ./xy.lis -file] &then &sys rm ./xy.lis &if [exists ./%outcov% -cover] &then kill %outcov% /* &wo %dir% /**************** ws.lis variables to read in ************* &sv funitX [open wsall.lis stat -r] &sv inline [read %funitX% rstat] &sv code1 [extract 1 %inline%] &sv lkid [unquote [extract 2 %inline%]] &sv midws [extract 3 %inline%] &sv nstcode [extract 4 %inline%] &type %code1% %lkid% %midws% %nstcode% &do &until %rstat% ne 0 /* /***** NOTE!! NEXT 5 SECTIONS - VERY IMPORTANT ***************** /************** define cases for selecting polygons *********** &sv case = 0 &if %nstcode% = 0 &then ~ &sv case = 1 &if %nstcode% = 1 and %midws% = 1 &then ~ &sv case = 2 &if %nstcode% = 2 and %midws% = 1 &then ~ &sv case = 3 &if %case% ne 1 and %case% ne 2 and %case% ne 3 &then ~ &sv case = 4 &if [exists ./temp/tmp%lkid% -cover] &then kill ./temp/tmp%lkid% &if [exists ./temp/dis%lkid% -cover] &then kill ./temp/dis%lkid% &select %case% /************* case 1 - non-nested watersheds *************** &when 1 &do arcplot reselect %dir%%cov%.pat info wslkcode = %code1% &sv code4 [show select %dir%%cov%.pat info 1 item ws_code1] quit reselect %dir%%cov% ./temp/tmp%lkid% poly res ws_code1 = %code4% [unquote ] n n /* clean ./temp/tmp%lkid% # 1 1 dissolve ./temp/tmp%lkid% ./temp/dis%lkid% ws_code1 centroidlabels ./temp/dis%lkid% INSIDE /* &end /**** case 2 - first "middle" watershed of nested sequence ****** /**** watershed nested in 1 downstream watershed AND has ****** /**** at least 1 nested above ******* &when 2 &do arcplot reselect %dir%%cov%.pat info wslkcode = %code1% &sv code2 [show select %dir%%cov%.pat info 1 item ws_code2] quit reselect %dir%%cov% ./temp/tmp%lkid% poly res ws_code2 = %code2% [unquote ] n n clean ./temp/tmp%lkid% # 1 1 dissolve ./temp/tmp%lkid% ./temp/dis%lkid% ws_code2 centroidlabels ./temp/dis%lkid% INSIDE /* &end /**** case 3 - second "middle" watershed of nested sequence ****** /**** watershed nested in 2 downstream watersheds AND has ****** /**** at least 1 nested above ******* &when 3 &do arcplot reselect %dir%%cov%.pat info wslkcode = %code1% &sv code3 [show select %dir%%cov%.pat info 1 item ws_code3] quit reselect %dir%%cov% ./temp/tmp%lkid% poly res ws_code3 = %code3% [unquote ] n n clean ./temp/tmp%lkid% # 1 1 dissolve ./temp/tmp%lkid% ./temp/dis%lkid% ws_code3 centroidlabels ./temp/dis%lkid% INSIDE /* &end /*********** case 4 - "nested" watersheds ********** &when 4 &do reselect %dir%%cov% ./temp/tmp%lkid% poly res wslkcode = %code1% or wslkcode = %code1% + 100 [unquote ] n n /* clean ./temp/tmp%lkid% # 1 1 dissolve ./temp/tmp%lkid% ./temp/dis%lkid% lake_id centroidlabels ./temp/dis%lkid% INSIDE /* &end &end /* end select block /*********** processing for all cases ***************************** addxy ./temp/dis%lkid% &sv funitY [open cent.lis stat -a] arcplot . . . remainder of .aml . . =================================================================== Currentness_Reference: Current as of 10/15/98 Maintenance_and_Update_Frequency: None planned unless problems reported. Access_Constraints: Requires ability to use ARC/INFO export files. Data_Set_Credit: Several past and current contract GIS staff at the Corvallis, Oregon EPA facility contributed to this coverage including: Colleen Burch Johnson, Gary Bishop, Patti Haggerty, Lorretta Schaffer, and others. In addition, some delineation and digitizing work was done by EPIC. If questions arise, contact Colleen Burch Johnson (cjohnson@mail.cor.epa.gov). Completeness_Report: Lakes and watersheds that were not sampled for chemistry (ex. landowner denied access) were not included in this coverage. A few "special interest" sites are not included, also. Horizontal_Positional_Accuracy_Report: unknown Vertical_Positional_Accuracy_Report: unknown Cloud_Cover: not applicable