WATERSHED CROSSINGS BY POSTMILE
Caltrans District 7 GIS Branch and Robert Wu, D7 Stormwater Liason, April 5, 2011.  Notes at end.
CO/RTE/PM	LEAVING	ENTERING	POS	COMMENT
LA 001 PM  00.000	Begin County	San Gabriel River	C
LA 001 PM  00.190	San Gabriel River	Los Cerritos Channel and Alamitos Bay	C
LA 001 PM  01.850	Los Cerritos Channel and Alamitos Bay	Colorado Lagoon	C
LA 001 PM  02.740	Colorado Lagoon	Los Cerritos Channel and Alamitos Bay	C
LA 001 PM  03.960	Los Cerritos Channel and Alamitos Bay	Los Angeles River	C
LA 001 PM  07.700	Los Angeles River	Dominguez Channel	C
LA 001 PM  09.240	Dominguez Channel	Los Angeles Harbor	C
LA 001 PM  11.220	Los Angeles Harbor	Machado Lake	C
LA 001 PM  17.380	Machado Lake	JG 6 of Santa Monica Bay	C
LA 001 PM  21.230	JG 6 of Santa Monica Bay	JG 5 of Santa Monica Bay	C
LA 001 PM  23.620*	JG 5 of Santa Monica Bay	Dominguez Channel	B
LA 001 PM  24.920	Dominguez Channel	JG 2 of Santa Monica Bay	D
LA 001 PM  25.670	JG 2 of Santa Monica Bay	Dominguez Channel	D
LA 001 PM  25.960	Dominguez Channel	JG 2 of Santa Monica Bay	D
LA 001 PM  29.220	JG 2 of Santa Monica Bay	Ballona Creek	C
LA 001 PM  30.660	Ballona Creek	Marina del Rey	C
LA 001 PM  32.180	Marina del Rey	JG 3 of Santa Monica Bay	C
LA 001 PM  36.700	JG 3 of Santa Monica Bay	JG 2 of Santa Monica Bay	C
LA 001 PM  40.750	JG 2 of Santa Monica Bay	JG 1 of Santa Monica Bay	C
LA 001 PM  46.790	JG 1 of Santa Monica Bay	Malibu Creek	C
LA 001 PM  47.420	Malibu Creek	JG 1 of Santa Monica Bay	C
LA 001 PM  60.080	JG 1 of Santa Monica Bay	JG 4 of Santa Monica Bay	C
LA 001 PM  61.500	JG 4 of Santa Monica Bay	JG 1 of Santa Monica Bay	C
LA 001 PM  62.800	JG 1 of Santa Monica Bay	End Route	C
LA 002 PM  02.390	Begin Route	JG 3 of Santa Monica Bay	C
LA 002 PM  02.580	JG 3 of Santa Monica Bay	Ballona Creek	C
LA 002 PM  03.680	Ballona Creek	Route Break	C
LA 002 PM  10.580	Route Restart	Ballona Creek	C
LA 002 PM  12.740	Ballona Creek	Route Break	C
LA 002 PM  13.100	Ballona Creek	Echo Park Lake	C	0.11 mile S. of Sunset Blvd.
LA 002 PM  14.350	Echo Park Lake	Los Angeles River	C	0.1 mile S. of Oak Glen Pl.
LA 002 PM  36.380	Los Angeles River	San Gabriel River	C
LA 002 PM  42.900	San Gabriel River	Los Angeles River	D
LA 002 PM  49.750	Los Angeles River	San Gabriel River	D
LA 002 PM  50.500	San Gabriel River	Los Angeles River	C
LA 002 PM  52.830	Los Angeles River	Antelope	C
LA 002 PM  62.530	Antelope	San Gabriel River	D
LA 002 PM  64.110	San Gabriel River	Antelope	D
LA 002 PM  74.700	Antelope	San Gabriel River	C
LA 002 PM  78.000	San Gabriel River	Antelope	D
LA 002 PM  79.900	Antelope	Mojave	D
LA 002 PM  82.260	Mojave	End County	C
LA 005 PM  00.000	Begin County	San Gabriel River	C
LA 005 PM  08.310	San Gabriel River	Los Angeles River	C
LA 005 PM  46.700*	Los Angeles River	Santa Clara River	B
LA 005 PM  87.360	Santa Clara River	Grapevine	C
LA 005 PM  88.600	Grapevine	End Route	C
LA 010 PM R02.155	Begin Route	JG 3 of Santa Monica Bay	C
LA 010 PM R03.610	JG 3 of Santa Monica Bay	Ballona Creek	C
LA 010 PM  16.570	Ballona Creek	Los Angeles River	C
LA 010 PM  30.100	Los Angeles River	San Gabriel River	C
LA 010 PM  45.760	San Gabriel River	Santa Ana River	C
LA 010 PM  48.200	Santa Ana River	End Route	C
LA 010 PM S00.000	Begin Spur	Los Angeles River	C
LA 010 PM S00.655	Los Angeles River	End Spur	C
LA 014 PM  24.800	Begin Route	Los Angeles River	C
LA 014 PM  25.500	Los Angeles River	Santa Clara River	C
LA 014 PM  53.530	Santa Clara River	Antelope	C
LA 014 PM  77.000	Antelope	End Route	C
LA 019 PM  03.980	Begin Route	Los Cerritos Channel and Alamitos Bay	C
LA 019 PM  08.400*	Los Cerritos Channel and Alamitos Bay	End Route	B
LA 022 PM  00.000	Begin Route	Colorado Lagoon	C
LA 022 PM  00.960	Colorado Lagoon	Los Cerritos Channel and Alamitos Bay	C
LA 022 PM  01.260	Los Cerritos Channel and Alamitos Bay	San Gabriel River	C
LA 022 PM  01.467	San Gabriel River	End County	C
LA 023 PM  06.750	Jurisdiction 1 of Santa Monica Bay	Sherwood Lake	C	0.05 mile N. of Mulholland
LA 023 PM  07.280	Sherwood Lake	Malibu Creek	C	0.6 mile N. of Mulholland
LA 023 PM  08.900	Malibu Creek	End County	C
LA 027 PM  00.000	Begin Route	JG 1 of Santa Monica Bay	C
LA 027 PM  09.300	JG 1 of Santa Monica Bay	Los Angeles River	C
LA 027 PM  20.060	Los Angeles River	End Route	C
LA 039 PM 17.900	Begin Route	San Gabriel River	B
LA 039 PM 44.400	End Route	San Gabriel River	B	Jct LA 2
LA 047 PM  00.000	Begin Route	Los Angeles Harbor	C
LA 047 PM  02.302	Los Angeles Harbor	Route Break	C
LA 047 PM  03.497	Restart Route	Los Angeles Harbor	C
LA 047 PM  04.161	Los Angeles Harbor	End Route at SR 103	C
LA 057 PM  00.000	Begin Route	San Gabriel River	C
LA 057 PM R08.200	San Gabriel River	Puddingstone Lake	C
LA 057 PM R08.950	Puddingstone Lake	San Gabriel River	C
LA 057 PM R12.212	San Gabriel	End Route	C
LA 060 PM  00.000	Begin Route	Los Angeles River	C
LA 060 PM  09.570	Los Angeles River	Legg Lake	C	0.06 mile E. of 164/60 Sep.
LA 060 PM  10.840	Legg Lake	Los Angeles River	D	0.27 mile W. of Peck Rd.
LA 060 PM  11.000	Los Angeles River	San Gabriel River	D
LA 060 PM  27.050	San Gabriel River	Santa Ana River	C
LA 060 PM  30.400	Santa Ana River	End County	C
LA 066 PM  00.000	San Gabriel River	Puddingstone Reservoir	C	Jct Baseline Rd.
LA 066 PM  02.360	Puddingstone Reservoir	San Gabriel River	C	0.04 mile W. of Williams Ave.
LA 066 PM  04.170	San Gabriel River	Santa Ana River	C
LA 066 PM  05.300	Santa Ana River	End Route	C
LA 071 PM  00.335	Begin Route	San Gabriel River	C
LA 071 PM  02.470	San Gabriel River	Santa Ana River	C
LA 071 PM  04.785	Santa Ana River	End County	C
LA 090 PM  00.921	Begin Route	Marina del Rey	C
LA 090 PM  01.740*	Marina del Rey	Ballona Creek	B
LA 090 PM  03.280	Ballona Creek	End Route	C
LA 091 PM  06.012	Begin Route	Dominguez Channel	C	Entering City of L.A.
LA 091 PM  08.430	Dominguez Channel	Los Angeles River	C
LA 091 PM  13.870	Los Angeles River	Los Cerritos Channel and Alamitos Bay	C
LA 091 PM  16.050	Los Cerritos Channel and Alamitos Bay	San Gabriel River	C
LA 091 PM  20.741	San Gabriel River	End County	C
LA 101 PM  00.000	Begin Route	Los Angeles River	C
LA 101 PM  02.570	Los Angeles River	Ballona Creek	C
LA 101 PM  08.900	Ballona Creek	Los Angeles River	C
LA 101 PM  29.260	Los Angeles River	Malibu Creek	C
LA 101 PM S00.000	Begin Spur	Los Angeles River	C
LA 101 PM S01.329	Los Angeles River	End Spur	C
LA 103 PM  00.000	Begin Route	Los Angeles Harbor	C
LA 103 PM  00.880	Los Angeles Harbor	Dominguez Channel	D
LA 103 PM  01.700	Dominguez Channel	End Route	D
LA 105 PM R00.000	Begin Route	JG 2 of Santa Monica Bay	C
LA 105 PM R00.500	JG 2 of Santa Monica Bay	Dominguez Channel	C
LA 105 PM R06.760	Dominguez Channel	Los Angeles River	C
LA 105 PM R17.110*	Los Angeles River	San Gabriel River	B	Sump drains all the way back to L.A. River.
LA 105 PM R18.145	San Gabriel River	End Route	C
LA 107 PM  00.000	Begin Route	Machado Lake	C
LA 107 PM  02.250	Machado Lake	Dominguez Channel	C
LA 107 PM  03.220	Dominguez Channel	JG 8 of Santa Monica Bay	D
LA 107 PM  03.760	JG 8 of Santa Monica Bay	Dominguez Channel	D
LA 107 PM  04.794	Dominguez Channel	End Route	C
LA 110 PM  00.000	Begin Route	Los Angeles Harbor	C
LA 110 PM  03.810	Los Angeles Harbor	Machado Lake	C
LA 110 PM  06.520	Machado Lake	Dominguez Channel	C
LA 110 PM  13.500	Dominguez Channel	Los Angeles River	C
LA 110 PM  19.940	Los Angeles River	Ballona Creek	C
LA 110 PM  22.900	Ballona Creek	Los Angeles River	C
LA 110 PM  31.912	Los Angeles River	End Route	C
LA 118 PM  00.000*	Begin County	Los Angeles River	B
LA 118 PM  14.000	Los Angeles River	End Route	C
LA 126 PM  00.000	Begin County	Santa Clara River	C
LA 126 PM  05.822	Santa Clara River	End Route	C
LA 138 PM  00.000	Begin Route	Santa Clara River	C
LA 138 PM  02.400	Santa Clara River	Antelope	B
LA 138 PM  74.900	Antelope	End County	B
LA 164 PM  01.385	Begin Route	Los Angeles River	C
LA 164 PM  01.570	San Gabriel River	Los Angeles River	C
LA 164 PM  02.800	Los Angeles River	Legg Lake	D
LA 164 PM  03.230	Legg Lake	Los Angeles River	D	0.1 mile S. of 60/164 Sep.
LA 164 PM  08.800	Los Angeles River	End Route	C
LA 187 PM  03.500	Begin Route	Marina del Rey	C
LA 187 PM  03.500	Begin Route	Marina del Rey	C
LA 187 PM  04.440	Marina del Rey	Ballona Creek	C
LA 187 PM  08.900	Ballona Creek	End Route	C
LA 187 PM R00.000	Begin Route	Los Angeles River	C	Jct 5
LA 210 PM R31.640	Los Angeles River	Peck Road Lake	C	0.36 mile E. of Santa Anita Ave.
LA 210 PM R36.000	Los Angeles River	San Gabriel River	C
LA 210 PM R46.330	San Gabriel River	Puddingstone Reservoir	C	0.11 mile E. of San Dimas Canyon Rd.
LA 210 PM R49.130	Puddingstone Reservoir	San Gabriel River	C	0.02 mile E. of College
LA 210 PM R50.470	San Gabriel River	Santa Ana River	C
LA 210 PM R51.850	Santa Ana River	San Gabriel River	D	Baseline Rd.
LA 210 PM R51.960	San Gabriel River	Santa Ana River	D
LA 210 PM R52.150	Santa Ana River	End County	C
LA 213 PM  00.000	Begin Route	JG 7 of Santa Monica Bay	C
LA 213 PM  00.120	JG 7 of Santa Monica Bay	Los Angeles Harbor	C
LA 213 PM  04.150	Los Angeles Harbor	Machado Lake	C
LA 213 PM  07.740	Machado Lake	Dominguez Channel	C
LA 213 PM  07.984	Dominguez Channel	End Route	C	Carson St.
LA 405 PM  00.266	Begin County	San Gabriel River	C	Atherton St.
LA 405 PM  00.420*	San Gabriel River	Los Cerritos Channel and Alamitos Bay	B
LA 405 PM  05.950	Los Cerritos Channel and Alamitos Bay	Los Angeles River	C
LA 405 PM  08.700*	Los Angeles River	Dominguez Channel	B
LA 405 PM  22.470	Dominguez Channel	Ballona Creek	C
LA 405 PM  37.130	Ballona Creek	Los Angeles River	C
LA 405 PM  48.600	Los Angeles River	End Route	C
LA 605 PM  00.000	Begin County	San Gabriel River	C
LA 605 PM  24.000	San Gabriel River	Peck Road Lake	D
LA 605 PM  25.100	Los Angeles River	San Gabriel River	D
LA 605 PM  26.000	San Gabriel River	End Route	C
LA 710 PM  05.000	Begin Route	Los Angeles Harbor	C
LA 710 PM  06.390	Los Angeles Harbor	Los Angeles River	C
LA 710 PM  32.700	Los Angeles River	End Route	C
VEN 001 PM  00.000	Begin County	JG 1 of Santa Monica Bay	C
VEN 001 PM  00.020	JG 1 of Santa Monica Bay	Ventura Coastal Streams	C
VEN 001 PM  07.480	Ventura Coastal Streams	Calleguas	C
VEN 001 PM  09.900	Calleguas	Revolon Slough	C
VEN 001 PM  10.800	Revolon Slough	Calleguas	C
VEN 001 PM  10.920	Calleguas	Revolon Slough	C
VEN 001 PM  13.260	Revolon Slough	Calleguas	C
VEN 001 PM  14.600	Calleguas	Oxnard	C
VEN 001 PM  17.630	Oxnard	Channel Islands Harbor	C
VEN 001 PM  19.630	Channel Islands Harbor	Santa Clara River	C
VEN 001 PM  21.075	Santa Clara River	Route Break	C	Joining US 101.
VEN 001 PM  21.250	Restart Route	Pitas Point	C	Separating from US-101.
VEN 023 PM  00.000	Begin County	Malibu Creek	C
VEN 023 PM  03.200	Malibu Creek	Route Break into Calleguas	C
VEN 023 PM  03.339	Restart Route from Calleguas	Calleguas	C
VEN 023 PM  18.560	Calleguas	Santa Clara River	C
VEN 023 PM  24.165	Santa Clara River	End Route	C
VEN 033 PM  00.000	Begin Route	Ventura River Estuary	C	at Ven 101
VEN 033 PM  04.090	Ventura River Estuary	Ventura River	C
VEN 033 PM  04.500	Ventura River	Ventura River Estuary	C
VEN 033 PM  05.560	Ventura River Estuary	Ventura River	C
VEN 033 PM  25.720	Ventura River	Santa Clara River	C
VEN 033 PM  26.190	Santa Clara River	Ventura River	C
VEN 033 PM  26.910	Ventura River	Santa Clara River	C
VEN 033 PM  42.800	Santa Clara River	Santa Maria	C
VEN 033 PM  57.500	Santa Maria	End County	C
VEN 034 PM  04.295	Begin Route	Channel Islands Harbor	C
VEN 034 PM  04.320	Channel Islands Harbor	Oxnard	C
VEN 034 PM  06.300	Oxnard	Revolon Slough	C
VEN 034 PM  07.300	Revolon Slough	Calleguas Creek	C
VEN 034 PM  07.600	Calleguas Creek	Revolon Slough	C
VEN 034 PM  11.860	Revolon Slough	Calleguas Creek	D
VEN 034 PM  13.170	Calleguas Creek	Revolon Slough	D
VEN 034 PM  13.320	Revolon Slough	Calleguas Creek	D
VEN 034 PM  17.600	Calleguas Creek	End Route	C
VEN 101 PM  00.000	Begin County	Malibu Creek	C
VEN 101 PM  01.210	Malibu Creek	Calleguas Creek	C
VEN 101 PM  14.050	Calleguas Creek	Revolon Slough	C
VEN 101 PM  20.080	Revolon Slough	Oxnard	C
VEN 101 PM  21.060	Oxnard	Santa Clara River	C
VEN 101 PM  25.900	Santa Clara River	Buenaventura	C
VEN 101 PM  30.650	Buenaventura	Ventura River Estuary	C
VEN 101 PM  31.530	Ventura River Estuary	Pitas Point	C
VEN 101 PM  43.530	Pitas Point	South Coast	C
VEN 101 PM  43.622	South Coast	End County	C
VEN 118 PM  00.516	Begin County	Santa Clara River	C
VEN 118 PM  02.820	Santa Clara River	Revolon Slough	C
VEN 118 PM  09.280	Revolon Slough	Calleguas Creek	C
VEN 118 PM  32.600*	Calleguas Creek	End County	B
VEN 126 PM  00.000	Begin Route	Buenaventura	C
VEN 126 PM  00.970	Buenaventura	Santa Clara River	C
VEN 126 PM  34.637	Santa Clara River	End County	C
VEN 150 PM  00.000	Begin County	South Coast	C
VEN 150 PM  02.530	South Coast	Pitas Point	C
VEN 150 PM  05.240	Pitas Point	Ventura River	C
VEN 150 PM  25.520	Ventura River	Santa Clara River	C
VEN 150 PM  34.400	Santa Clara River	End Route	C
Notes:  This report should generally be consistent with the 1:200,000 scale watershed boundary maps also published by GIS Branch via Internet and PDF.  For some Caltrans projects, the listing may be a convenient alternative to those maps for finding associated watersheds.  Neither the maps nor this list are certain, especially where routes pass near watershed edges.  It is derived from various sources, of varying positional accuracy, but mostly EPA and Department of Water Resources watershed mapping, with the HQ Office of GIS postmile service.  Some locations or purposes may require further study of drainage structures.  Consult the glossary below, and contact GIS Branch or Stormwater Branch for more information.
Glossary--
CO/RTE/PM	County, Route, and Postmile of estimated crossing of route centerline. Prefix added where significant.  (e.g. LA-101 spur and 10 spur) An asterisk * indicates some verification performed.  (see also POS.)
LEAVING	The name of the watershed behind (in the direction of decreasing postmiles) this postmile point. The watersheds are really sub-watersheds defined by differing pollution control regulations.  For example, at one time, we mapped Marina del Rey "watershed" because a TMDL agreement was under study.  Even after such a TMDL agreement is officially accepted, such a small pollution control regulation area may never become part of the published statewide Cal-Water system.  If you ask, we can provide a table showing how our watershed regulation areas fit under those larger watersheds.
ENTERING	The name of the watershed regulation area ahead of (in the direction of increasing postmiles) this postmile point.
POS	Positional accuracy "letter grade" for this watershed crossing. "A" = Complete study of drainage structures to delineate a boundary accurate enough for any purpose.  Neither a postmile nor our usual maps could accurately represent such a detailed boundary, so a special map would need to be prepared for each crossing, or a zoomable CADD or GIS map employed.
	"B" = Superficial analysis of drain plans and surface topography to delineate watershed limits with better accuracy than statewide GIS sources alone.  Sometimes the analysis was performed by City engineers or consultants, sometimes by Caltrans Hydraulics or GIS staff.  "B" listings are about the same accuracy as a good postmile fix, which generally means +/-100 feet along the centerline.  Still, mapping bigger than our standard 1:200,000 scale will be required to see the detail near these crossing points.
	"C"= Simple intersection of TeleAtlas roads with watersheds from DWR and other sources, including digitizing off paper maps.  Little consideration may have been given to subsurface structures.  In at least one case, a sump rendered the "C" mapping incorrect by miles!  However, for low-risk purposes, "C" is probably the only boundary available.
	"D"=Same as "C" except that the watershed boundary appears to be meandering along our route, meaning you should consider asking for a "B" accuracy study.
COMMENT	To clarify the location or special considerations.