Coastal_systems_and_issues_(Christian)

Coastal Systems and Issues
Associated with Them
Bob Christian
Three overarching concerns that may challenge
application of approaches to coastal plain:
–Hydrogeomorphological issues influencing
modeling
–Ecological issues influencing choice of ecological
integrity choices
–Kinds of water withdrawals

Hydrogeomorphology: the area is flat!!
•Topographic relief
makes watershed
designations difficult
Hydrogeomorphology: the area is flat!!
•Slope is low
–Flow often not high
enough to move
heavy material and
scour
•Riffle and pool
structure with rocks
less common
•Bottom often
muddier
Hydrogeomorphology: the area is flat!!
–Reverse flow is common
•Tidal action
–Significant geographic differences in
tidal influence
»Northeast within and behind
sounds – wind dominated
•Slow frequencies, irregular
and long durations
»Southeast – astronomically
dominated
•Short frequencies and regular
»A spectrum of possibilities
between end-members
•Backflow from larger rivers during high flows
Water levels: LOLA
Water levels: PKS
23%
59%
Harmonic analysis by J.T. Morris
From Voss 2009
tidal range: ~60 cm
tidal range: ~8 cm Tides
Hydrogeomorphology: the area is flat!!
–High connectivity with adjacent wetlands
•Overbank flow can increase cross sectional area and
volume significantly
From Riggs and Ames
Hydrogeomorphology: the area is low!!
•Gaging stations are limited

Hydrogeomorphology: the area is
low!!

•Salinity
–May range from 0 to >30
–May be affected by
water use

Hydrogeomorphology: the area is low!!

•Sensitivity to sea-level rise

Human alterations dominate
–Obstructions – dams, culverts – block fish passage
and alter flows
–Channelization
–Agricultural ditching
–Road side ditching
–Desnagging/Snagging
–Navigational dredging

Human alterations dominate
–Agricultural ditching
–Road side ditching
–Channelization
–Snagging
–Navigational
dredging

Ecology
•Established habitat-based
foundation through the Coastal
Habitat Protection Plan (CHPP)
developed by NC DMF
–Habitats germane to EFSAB

Ecology
•Species are often different than those found in inland
waters or having different ecology from that inland.
–Examples (Some require Fisheries Management Plans involving
flows)
•Anadromous fish (upstream spawning)
–Blueback herring and alewife (under consideration for endangered status)
–American shad
–Atlantic sturgeon (endangered)
–Shortnose sturgeon (endangered)
–Striped bass (stock status – concern)
•Catadromous fish (marine spawning)- eel – (stock status - depleted)
•Estuarine species – some of the common low-salinity species that
occur in river systems: southern flounder, Atlantic croaker, spot,
menhaden, bay anchovy, blue crab, white shrimp, striped mullet
Table 2.3. Spawning seasons for coastal fish and invertebrate species occurring in North Carolina that broadcast planktonic or semidemersal eggs. [Sources: USFWS species profiles (see literature cited: reference titles beginning with Species Life Histories and Environmental Requirements), DMF fishery management plans, Funderburk et al. (1991), Pattilo et al. (1997), Luczkovich et al. (1999), NOAA (2001), and DMF (2003a)]
Species
Winter Spring Summer Fall
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
ANADROMOUS FISH
Alewife
American shad
Blueback herring
Striped bass
ESTUARINE AND INLET SPAWNING AND NURSERY
Atlantic silversides
Bay anchovy
Bay scallop
Blue crab
Black drum
Cobia
Hard clam
Inland silversides
Oyster
Red drum
Spotted seatrout
Weakfish
MARINE SPAWNING, LOW-HIGH SALINITY NURSERY
Atlantic croaker
Atlantic menhaden
Brown shrimp
Southern flounder
Spot
Striped mullet
White shrimp
MARINE SPAWNING, HIGH SALINITY NURSERY
Black sea bass
Bluefish
Gag
Gulf flounder
King mackerel
Pinfish
Pink shrimp
Sheepshead
Spanish mackerel
Southern kingfish
Summer flounder

Black squares indicate peak spawning. Cross-hatched squares indicate spawning period.

Spawning Location and
timing are major factors in
categorizing species
Table 2.19. MFC and WRC fish habitat designations in CHPP management regions.
Note: the area of PNA, Permanent SNA, and IPNA does not include tidal areas
between the mean high water (or normal water level) and the apparent shoreline
(i.e., wetland edge). The miles of AFSA includes both streams and shorelines.
Phys. region
CHPP
region
PNA
(acres)
PSNA
(acres)
IPNA
(acres)
AFSA
(miles)
AFSA
(acres)
Coastal Plains 1 166 168 16,269 2,413 153,894
2 12,166 46,875 8,985 1,450 49,995
3 14,557 0 700 101 829
4 14,786 292 4,391 821 13,491
Piedmont 1 0 0 303 0 2
2 0 0 0 55 375
4 0 0 634 0 0
TOTAL ALL 41,675 47,336 31,283 4,840 218,586

Ecology
•Some portions of coastal rivers
(oligo-mesohaline) support
greater species richness than
polyhaline and freshwater due
to overlapping ranges,
seasonal variations in salinity,
but will vary naturally due to
environmental conditions and
seasonality.
Table 2.4. Physical spawning (adult) and egg development requirements for resident freshwater and
anadromous fishes inhabiting coastal North Carolina.

Species
Salinity (ppt) Temperature (C)
Dissolved oxygen
(mg/l) Flow (cm/s)
Other
parameters
Adult
Spawn/
Egg Adult
Spawn/
Egg Adult
Spawn/
Egg Spawning Spawn/ Egg
Alewife [S] 0-5 [S] 0-5
[O] 0-2 [S] 11-28
[O] 17-21 [S] >3.6 [S] >4 [O] slow
current
[S]
Suspended
solids <1000
mg/l
American
shad [S] 0-18 [S] 0-18 [S] 10-30 [S] 13.0-
26.0 [S] >5 [S] 30-90
Blueback
herring [S] 0-5 [S] 0-22
[O] 0-2 [S] 14-26
[O] 20-24 [S] >5 [O] strong
current
[S]
Suspended
solids <1000
mg/l
Striped
bass [S] 0-5 [S] 0.5-10 [S] 20-22
[S] 12-24,
[O] ~18-
22
[S] >5
[S] 30.5-
500, [O]
100-200
Yellow
perch [S] 0-13 [S] 0-2 [S] 6-30 [S] >5
[S]
Suspended
solids <1000
mg/l
White
perch [S] 5-18 [S] 0-2 [S] 10-30 [S] 12-20 [S] >5
[S]
Suspended
solids <100
mg/l
Sturgeon,
Atlantic
[S] 0 to
>30 [S] 0-5 [S] 0 to
>30 [S] 11-20
Sturgeon,
Shortnose
[S] 0 to
>30 [S] 0-5 [S] 0 to
>30 [S] 5-15
[S] = Suitable, and [O] = Optimum

Physical factors
and flow
influencing
select species
Ecology
–DWQ has different programs for Index of Biotic Integrity for
coastal plain streams.
•Hydrogeomorphology (Very low flows, channel
modifications, riparian zones, depth)
•Biota
–Fish
–Benthic macroinvertebrates
»Swamp method
–I defer to Jay and Tom on details
–There is no estuarine IBI for coastal waters
Ecology
–Wetlands and their services are inextricably linked
to waterways
Kinds of water withdrawal issues
•Community water supply
–Not necessarily based on surface withdrawal and
reservoir use.
–Groundwater and desalinization
–Increasing demands with coastal population growth
•Non- community water supply
–Mining
–Agriculture
–Industry (power plants)

Summary
•Coastal plain waterways are potentially different in
numerous ways:
–Hydrogeomorphological issues influencing modeling
–Ecological issues influencing choice of ecological integrity
choices
–Kinds of water withdrawals

•All of these contribute to the challenge of applying
procedures from inland to the coastal plain.

•I’ve described some of the problems. Can we find
solutions?