The following information is from a presentation at the Cal Poly Pomona conference in 2016 by Robert Reese. To see a PDF of the whole presentation CLICK HERE

Some definitions for Water Boundaries

GENERAL WATER BOUNDARY CLASSIFICATIONS

lacustrine – (from Latin lacus, meaning lake) of or pertaining to lakes
riparian – (from Latin ripa, meaning river bank or riparius, meaning river) of or pertaining to rivers and streams
littoral – (from Latin litus, meaning the shore), in particular the sea; a coastal region

TIDES AND DATUMS

National Tidal Datum Epoch (NTDE) – a particular 18.6 year interval during which tide observations are used for datum computations (1941-1959) (1960-1978) (1983 – 2001)
Metonic cycle – 19 years or 235 lunations, or the interval after which the moon’s phases occur on the
same day of the year; named after Meton, a fifth century BC Greek astronomer (29.53X235=6939.55 days @ 19 yrs)
Diurnal – daily; occurring once per day (for tides)
Semi diurnal – half day; occurring twice per day (for tides)
Mixed tide – semi diurnal tides with large inequalities between highs and between lows
Tidal datum – plane related to one of several tidal heights
MHHW – Mean Higher High Water: arithmetic mean of all the higher high waters over 19-year metonic
cycle (1×365.25×19 = 6,940)
MHW (~OHW, ~MHT) – Mean High Water: arithmetic mean of the high water heights over a specific 19-
year metonic cycle (2×365.25×19=13,880). Note: “ordinary” is generally synonymous with “mean”,
but its use is discouraged. Note: Mean High Tide is discouraged.
MT (MTL) – Mean Tide or Mean Tide Level: midway between Mean High Water and Mean Low Water.
MSL – Mean sea level: arithmetic mean of hourly water elevations over a 19-year metonic cycle
(24×365.25×19=166,554)
MLW – Mean Low Water: arithmetic mean of the low water heights over a specific 19-year metonic cycle
(2×365.25×19=13,880)
MLLW – Mean Lower Low Water: arithmetic mean of all the lower low waters over 19-year metonic cycle
(1×365.25×19 = 6,940)
Neap tides – those tides of decreased range occurring when the moon is in quadrature. Also MHWN,
MLWN.
Spring tides – those tides of increased range occurring when the moon is in opposition, at or near syzygy. Also MHWS, MLWS.

TIDAL

tidelands – those lands covered and uncovered by the ebb and flow of the sea; lands between the mean
high and mean low tide
submerged lands – those lands continuously covered by the sea and large lakes
uplands – those lands adjacent to bodies water; lands above OHW; lands situated above riparian lands
and having no riparian rights
bight – wide curving bend in shoreline forming a bay
headlands – narrow piece of land jutting out into water; a point at which there is an appreciable change
in direction of the shore

NON-TIDAL

alluvion – (alluvium) the soil that is deposited on the edge of a river or lake or sea gradually and
imperceptibly
swamp – low lying land saturated with moisture and overgrown with vegetation but not covered with
water; land at elevations below the upland such as wouyld be wet and unfit for agriculture without
artificial drainage
marsh – an area of low lying wet ground subject ot freuent or regular flooding or ordinarily covered with
water. Usually salt marsh.
overflowed lands – lands which are annually or periodically subject ot natural flooding during the normal
planting, growing or harvesting seasons and rendered unfit for cultivation of local staple crops.
thread – center of the main channel of a stream; center of navigational channel
thalweg – the “down way” – the course taken by boats going down a stream or river; the middle of the
main navigational channel, the line of the lowest part of a valley or channel
median line – the line every point of which is equidistant from the nearest point on opposite banks or
other reference line (1)
medium filum acquae – geographic middle of a river or stream (1); median or medial line

PHYSICAL CHARACTERISTICS AND CHANGES

natural – the undisturbed condition
artificial – non-natural, or caused by man
sudden – a subjective term indicating perceptible, recognizable changes
imperceptible – a subjective term indicating unrecognized changes

LOSS

avulsion – sudden changes of loss of land by separation
erosion – gradual disappearance of land by water “eating away”
submergence – disappearance of land underwater and formation of

GAIN

accretion – imperceptible accumulations of land by deposition
reliction – the addition of land by permanent recession of waters
construction – artificial accretion or deposition through one means or another

NAVIGABILITY

navigable waters – waters which afford a channel for useful commerce or travel
ocean, river, lake, streams
navigability at law = navigability in fact
state navigability
federal navigability

TITLE

other sovereign recognition – Treaty of Guadalupe Hidalgo –
public trust doctrine – California holds navigable waters of the state in trust for the people of California
public trust lands held by local government – also held in trust for the state and thus for the people of
California
public trust lands held by private entities – may be subject to public trust

MEASURE

geographic mile – same as nautical mile
nautical mile – international unit of measure used in sea and air navigation: 1852 meters » 6076 feet »
1/60 degree of latitude at equator
statute mile – 5280 feet
league – three nautical miles
fathom – 6 feet (old English for outstretched arms)

MISCELLANEOUS

Ipso facto – by the fact itself
Ex rel – ex relatione – on behalf of or upon relation or upon information
Certiorari, writ of – to be informed of; pertains to request for information by higher court of lower court to
inspect record for possible review