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't lth April 201 I
Ms. Noeleen Roche
Program me Officer
Environmental Licensing Programme
Office of Climate, Licensing and Resource Use
EPA Headquarters
PO Box 3000
Johnstown Castle Estate
Co. Wexford
Re: WO9049 Dumping at Sea Permit Application #or Dredging Works at Waterford City
Marinas
Reg No. SOOO6-01
Dear M s . Roche,
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Please find enclosed a response prepared by Mr. G er Morgan of Aquatic Services Unit (ASU):
UGC with regard to the suhrnission made by Dr. James King of tnland Fisheries Ireland (IFI).
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In summary, it is considered fhat comparisons of the Suir Estuary with the Loire and Gironde
estuaries in France are misleading: particularly taking account of factors s u c h as the populaiion
catchments associated with the French estuaries as well as the greater number of industrial
so~irceslikely to impact on them compared to the Suir, On examination of the papers referenced
in the tetter from IF! it IS noted that low dissolved oxygen levels in these estuaries are 'Ihe main
reasons for fish mortalities as opposed to turbidity levels. The same effects are unlikely in the
Suir where dissolved oxygen levels are considerably higher. Please refer to the letter from AStl
for further detail.
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consideration:
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In addition to the response prepared by ASU, the foilowing point should afso be taken into
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The Environmentai Objectives (Surface Waters) Regulations 2009 address the
requirements of the Water Framework Directive and set out h i t s for nutrients and
pollutants in surface waters irtctuding transitional waters. There are no limits set out for
suspended solids/turbidity. The submission refers to the fact that concerttt-ation ranges
equating to the status categories of High-Good-Moderate-Poor-Bad are being proposed
in France in the context of the Water Framework Directive. However the quesfion of
relevance of such ranges must be considered for estuaries whet-e nattiratly high levels of
suspended solids occur. In this context, i.e. natural variation, how would turbidity levels
be controlted? Furthermore, dredging activities given their temporary nature are unlikely
to affectthe overall status of the estuary to be achieved by 2015.
As se1 out in the response prepared by ASU, the risk posed to adult migrating shad from the
proposed dredging is low, neverheless the dredging commencement date will be pushed back
to May 23rd by which time the bulk of the migrating shad will be in the spawning grounds
upstream of Carrick-on-Suir with only small nutmbers still moving up past Waterford City.
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In relation to Dr. King’s suggestion that it may be an option to dredge in the diy with terrestrially
based piant working from the key or from the sand bars to load trucks for dumping to landfill
sites we coinment as follows:-
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Low water at ordinary spring tides is 05mOD Pooibeg and at neap tides is 1 50 mOD
Poolbeg i,e the average low water level in Warerford is 1-00mOD Poolbeg. At that level
6-8% of the volume to be dredged is exposed. Therefore the amount of material that
could be dredged ‘in the dry’ is only 6-8% of the total volume to be removed.
I presume the reference to sand bars refers to the silt and sand deposits along the river
hank. it would not be practical or safe to land a backhoe on this surface given the soft
composition of the material and its exposure to tidal waters.
loading trucks with material dredged from the river and transporting the material through
the streets of Waterford City would be totally unacceptable to Waterford City Council.
Mounting a long reach excavator on the quays in Waterford is not a feasible option.
Keverflow car park was developed by reclaiming the area from the river and it is faced
with reinforced earth panels. It has a wide footpath along the riverside and a flood
protection barrier The structure was not desigixx3 to support the large loads whlch a
long reach excavator would impose. The car park is privately owned and operated and
any attempt to carry out dredging works from the car park is likeiy to meet strong
resistance due to the risk of damage, loss of revenue and the mess which such an
activity WO U Id g e nerat e.
A t the f\:lilleniiim Plaza there is insufficient space to operate a backhoe. The Clyde Wharf
which is c h e s t to Marina A2 is in poor cotidition and even if a backhoe could be
positioned thew it would be scverely restricted by the Derrick Crane, the flood protection
barrier and ?:e redestrian walkway. Finalty the quay wall at Adelphi Quay is in poor
conclition and the reach required is excessive.
Rates of prodlicticn %r backhoe dredging are low.
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Taking these points into account it is apparent thai backhoe dredging from the bank 3r from the
shoreline is not a suitable option.
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The existing marina pontoot7s can be temporarily removed to facilitate the dredging works, It is
much more difficutt to temporarily ren-iove t h e gangways atid the piles wiil remain in place for
the duration of the works.
These wiil pose a very significant impediment to all dredging works along the marinas b u t will
affect plough dredging much less due to the relatively small size of the equipment by
comparison with the much larger eyuiptnent associated with trailer suctbn dredgers, split
hopper barges and pontoons with backhoes.
In considering the submission presented by Dr. King and in order to prevent further deiays to
the permitting process we very reluctantly accept the delayed commencement date of May 23rd
for plough dredging as proposed by ASU in their letter. This cornpresses the duration of the
dredging campaign to 5 weeks which provides for no programme contingency and restricts our
ability to integrate the dredging works with works to fenderitq which must atso be completed
prior to the arrival of the Tall Ships.
In conclusion
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the use of backhoe dredging as the primary mechanism for removal of deposits is not a
practical option, The method is too sfow and is also very expensive and econoniicatly
Utiviable.
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Timing of the works within the low tide portion of the tidal cycle is not a reasonable
option. The works will involve full time dredging for a minimum 12 hours per day for the 5
week period.
Discreet localised digging wilt result in these pockets quickly infiltiny again resulting in
the need to carry out repeated cycles of dredging to achieve the required levels. By
covering long runs with each passage, plough dredging will gradually reduce the bed
level over the area being dredged.
The precautionary principle approach proposed by Dr, King is severely restrictive and onerous
and if incorporated in conditions attached to the Permit may put ihe Tall Ships event at risk. W e
therefore request that the EPA in considering the conditions to be attached to the Permit take
account of the high dissolved oxygen levels and high turbidity ievets which exist in the Suir
which are not comparable with conditions in the Loire and Giroiide rivers in France where
dissolved oxygen levels are very IOW, turbidity levels are very high and the area is industrialised
to a far greater extent.
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W e also propose that the proposed dredging works be monitored for a number of parameters
such as turbidity, dissolved oxygen levels and signs of fish in distress. The operation can be
temporarily halted until these parameters (in combination or singularly as set out in the ASU
fetter) return to ambient levels before proceeding.
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If you have any ftrrther queries, please do not hesitate to contact the undersigned.
L/I
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Y U Urs si n(:erer y
For MALONE O'REGAN
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11-04-2011
Response to Dr. James King's Letter to the Environmental Protection Agency
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Gerard Morgan M S c , manager of the Aquatic Services U n i t has been requested by Malone O'Regan,
Consulting Engineers acting on behalf of Waterford Corporarion to comment on the submission of
Dr. fames King of inland Fisheries Ireland to the Environmental Protection Agency (EPA) dated March
25'" 2011 concerning the dredging application in respect of the Waterford Quays for the forthcoming
Tall Ships race.
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I have read Dr, King's report and I would like to draw attention to the illustrative use he makes o f
studies from French estuaries, where I feel coniparisons with the Suir Estuary at Waterford City are
misleading. Moreover, his reference to the sensitivity of iai-val rather than adult fish to suspended
solids exposui~eI ~z/ouldcontend is overly cautious.
French Estuaries v the Suir Estuary at Waterford City
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Accor-dingto Ut-. King 'Studies on the Loire (Sauriau et al., 1993) huve imp!icuted a convergence of
high ttirhidity, cor!tribr.iting to anoxic conditions, with mortality of adl;lt milllet in their ~ w w u r d
rniyraliorr ,from the estuary'. While this is iridcied true, it is important lo point out thai; it is the
presence of extremety IOW oxygen concentrations and not the high turbidity per se, which the
.authors indicate to tic rcsponsiblc for the high mullet mortalities referred to. 'Mortc!ities c m
observed when shoals of fisii meet Iiypoxic: wntcr. In sur?i.mc:-, freshwater dischui-ge is 10~4)arid
oxygen problems are mainly r c b t e d to the tidal siiuution arid eutrophication of the river. it? periods
of high tidal range turbidity is r-nnximnl a/,d d'egradcition gf resitspended orgcrnic rnnteriaf generates Q
totcrl clnoxia that is incompatibie with the survival of fish'. (Sauriau, 1993). In fact jn a slightly later
paper reporting on the same work (Sauriau, et al., 1994), the same authors report on tank
experiments where tnullet are exposed to fully aerated conditions and hypoxic conditions in turbid
a n d clear waters. These showed that when mullet were kept in highly turbid water (540-640mg/l similar to ambient levels in t h e 'TMZ of the Loire) for 1 2 hours that thet-e was 100% survival, the
same as in an aerated control tank without turbidity, and in two other test tanks (one dear and one
turbid) where the dissolved oxygen was allowed to drop to less than lnig/l, the rate of mortality
with time was virtual!y the s a m e in b o t h tanks over the 1.2.hour test period i.e. "50% n7or:ality after
5 hours and 90-100%mortality after 3.0 hours (Sauriau, et al., 1994,Fig 7 ) .
fn this context, it is important to poinx out chat conditions in the Loire study area during the seasol?
of reported fish mortalities i.e. 'high levels of organic matter are observed in the estircrry iri .s~mmer
as a result of both river' eutrophication nnd sewage and industrial discharges' (Snrrriau et al.,19941,
' T M Z = Turbidity Maxirnun; Zone
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ff we compare the conditions reported on the Loire with those reported for the River Suir at
Waterford City the contrast is cleat-.
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DGring routine water quality monitoring ir! the Suir Estuary, the EPA recorded the following dissolved
oxygen a n d levels at Waterford Bridge:
‘ b b k 5. Dissolved Oxygen and B O B levels at Waterford Bridge (Daca EPA, Michael Neill et
Kilkepny labs}
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These data show that dissolved oxygen levels are at high leveis of saturation in the Suir within the
Waterford City stretch and wi!l therefore not pose any synergistic stress on migratory fish during the
proposed dredging. It is also noticeable that bottorn dissolved oxyget? levels are generally barely
lower than the surface levels, indicating a iow sediment oxygen demand, which is further supported
by coritinuous moiiitoring undertaken at the Waterford City Marina over several days in July 2001
(Neil/,2001,page 26) , ~ h k showed
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that during-tidally induced turbidity peaks dissolved oxygen
rarely dipped beiow 90% saturation.
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bear no resemblance to the Waterford City stretch of the Suir in M a y ar?d June. Furthermore in the
Loire study, dissolved oxygen during the stirnmer-auttimr! period (August to October) rarely rose
above 4mg/J (Sauriau et al.,1993) and often fell to exceptionally low levels, as on P.~igust23’d1990
when oxygen levels of G.Smg/l (i.e. 5 % saturation) extended for a 25kn: stretch of the study area
(Sauriau et al., 1994). These would be exceptionally stressful conditions it? a n y estilary, even one
with no turbidity. Thus rhe authors conciude (~354);’Our observat~onsof summer fish-kills in the
estuary, oxygen tolerance in the laboratory, and field measurements of physical parameters suggest
thnt in the wellmixed loire Estuary, fish die as u direct result of oxygen depletion’. It is itnportant to
point out that nothing in either paper suggests that turbidity is a contributory factor tc the observed
mortalities.
Later in his letter Dr. King refers to large mortalities of shad which occurred in another French
estuary the Gironcle in 2003, These were attributed to d r o u g h t level flows in incoming channels. He
goes on to suggest that ‘the low level of i/ifiows may have exacerbated turbidity conditions in the
estuary thut may, in turn, have contributed to an adverse condition in the water body for the shad, as
with the Mullet studies in the Loire’. However, he doesn’t indicate where in this very long estuary
the mortalities were recorded nor docs he provide any water quality data that would support this
suggestion.
As in the case of the Loire, it is important to note the very significant differences in the water quality
of the Girondc estuary a n d that of Waterford City reach of the River Suit-. For exampie the Gironde
Estuary, has exceptionally high turbidity levels, ranging from 1000rng/l (surface) to 10,00Omg/l
(bottom) Latouche and Jouanneau f1994j. Furthermore, the Gironde sediment is contaminated
with heavy tnetals and persistent organic pollutants (quoted in Etcheber et al., 2011). But more
importantly both branches of the fluvial estuary experience depressed oxygen levels in suminer in
addition to very high turbidity levels. I i i the Garonne branch at Bordeaux - (with a metropolitan
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population of 1miilion inhabitants) and the Dordogne branch at libourne, tidally-associated drops in
oxygen range from 2540% saturation at Bordeaux and 4575% saturation at Libourne (i.e.70-75s at
high water and 45-5076 at IOW water) (Etcheber et al., 2011).
Shad Sensitivity to Suspended Solids
In respect of the sensitivity of shad to sediment, Or. King refers to a paper on American shad (Alosa
spandissirna) which indicated that in lab experiments where shad larvae were exposed on a
continuous basis to suspended solids 100mg/l for 4 days, mortalities occurred (in that case 13%). It
is important to point here that shad larvae wit1 not be present in the Suir a t Waterford Bridge in M a y
and June, a point acknowledge by Dr. King in his letter. Furthermore, adults in general are far more
tolerant of elevated suspended solids than larvae of the same species a n d w e can expect that this
will be no different for twait shad.
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In their review paper on the impacts of suspended solids from estuarine dredging (Wilber and
Clarke, 2001) show that in most cases where adult fish are exposed to suspended solids of 1000mg/l,
continuous exposure for less than i day rarely gives rise to mortality, which generally required either
higher concentrations or longer- exposures before mortality begins. The authors show that fish are
likely to be less susceptible to native sediments (i.e. from the estuaries t h e y pass through) than to
those such as Fuller's Earth used in lab experiments.
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Suspended soiids level of 1000ing/l may arise during the proposed dredging in Waterford, but if so,
probably only close to the dredger, dropping off rapidly with distance. Fish however, are unlikely to
experience nrortality as the review of Wilber and Clarke (2001) indicate that continuous exposure
for at: least a day would be required before mortality begins to occur. When this is considered in
the light of the very high natural turbidity's in for exatnple the Severn, Gironcle and Loire estuaries,
through which several anadromous and catadramous species including shad migrate, combined with
the fact that dredging ai thr? Waterford quays will not occur during the hcmrs of darkness, then it is
clear that the risk to migrating a d u l t shad is likely to be low. This risk further is rcduced b y the fact
t h a t oxygen levels in the Suir at the site are high (Neiil, 2001, 2003, 2005) a n d that the sedit-iient is
IGW In contaminant ~w:~l:;,Ako, the fact that the dredging will take place 0:) the southern side of the
channel, allowing fish to move through lower turbidity water etsewhere in the channel, wi!l aiso be a
risk r e d u c ~ n gfactor.
Recommendations
Even though the foregoing paragraphs, indicate that the risk to adult migiating shad from the
proposed dredging a s proposed is {ow, nevertheless, considering the in7portance of the shad as a
protected Annex I t species, the dredging comnwncement date wtit be pushed back to M a y 23rd by
which time the bulk of the migrating shad will be on the spawning grounds upstream of Carrick-onSuir with only small numbers still tnoving up past Waterford.
As a further safeguard, the operation wilt be monitored for turbidity levels, dissolved oxygEtn levels
and signs of fish in distress as follows:
If (i) turbidity levels more than 100m from the dredger exceed SOOmg/l above
background levels (or the equivalent as NTU) or ( i i ) turbidity levels more than 100m
from the dredger exceed 300nig/l above background levels (or the equivalent as NTU)
combined w i t h a drop in dissolved oxygen to below 65%, or (iii) if oxygen alone at the
same point drops below 65% saturation or (iv) if protected fish are observed to be in
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EPA Export 13-04-2011:03:59:40
distress, the operation will be temporarily halted until these parameters r e t u r n to
ambient levels before proceeding.
References
Elcheber, H., Schmidt, S., Sottoiichio, A., Maneux E, Chabaux, G., €scalier J.-M.,Wennekes, H.
Derriennic, Schineltz M.,Qu&mkner, L., Repecaud M, Woerther P., and P. Castaing (2011)
Monitoring water quality in estuarine environments: lessons from the MAGEST
monitoring program in the Git-ondeftuvial-estuarine system. Hydrol. Farth Syst. Sci., 15,
831-840,
Latouche, C.; Jouanneau, J. M., 1994: Etude de la dynamique de l’eau et des sbdirnen‘is. in: L i v ~
blanc de I’Estuaire de /a Gironde. J. L. Mauvais and J.F. Guillard (Eds). IFREMER, Agence de
l’eau Adour-Garonne Publishers, pp. 8-21
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Neil, M . (2001) Water qiinlity in the Suir/Barrow/fV,ore Estuary, summer 2001, A report
commissioned by Waterford Corporation, the Coirnty Councifs of Waterford, Wexford,
Kilkenny, Tipperary SR arid Carlow and by the EPA. €PA, Killtenny.
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Neil, M . (2003) Wafer q u ~ i i t y7:j the Surr/Garrow/Nore Estuary, S L J M M C ~ 2003. A report
commissioned by Waterfwd Corporation, the County Councils of ‘Nateriord, Wexford,
Kilkenny, Tipperary SR a n d Carlow and by the €PA. €FA, Kiikenily.
Neil, M . (20051 Water- quality in the Suii-/Barrow/Nort? Estuary, summer 2005. A report
cotninissioned by Waterford Corporation, the County Councils of Wa:erford, bvexford,
Kilkenny, Tipperary SR and Cariow and by rhe [PA. €PA, Kilkenny.
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Sauriaa PI-G., Robin J.-P. & Marchalid J. (1993)ies mortalities estivalss du mulet Liza rarnada en
Loire: dysfonctionnei-nentcycitque de rote de voie de migration d’un estuaire. 8dl. €CO!.
24, p p 87-91.
Sauriaii P.-G.,Robin J . - P . 8: Marchand J . (:1994) Effects of excessive organic enrichment of the Loire
estuary on the downstream migratory patterns of the amphihaline Grey Mullet Liz3
ramada (Pices:Mugihdaef in Chnnges in Fluxes in Eztual-ies eds. K.R. Dyer and K.J. Orth.
Olsen & Olsen (Denniai-k) International Symposium Series. 349-356.
Wilber, D.H. a n d Clarke, D.G. (2001)Biiiiogicaf effects of suspended sediment: a r w i e w of suspended
seditnent impacts on fish a n d shellfish with relation to dredging activities in estuaries.
North Americon lournnl of Fjsherics Management. 21,355-875.
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