South Canterbury Coastal Streams (SCCS) limit setting process:
Wainono Lagoon: Current state and Scenario 1 (pre HDI & WD)
Ned Norton
20 June 2013
Introduction
This report provides a high level summary of the current biophysical state of Wainono Lagoon and
the predicted state under so-called Scenario 1 (pre HDI & WD), which includes three alternative river
minimum flow and allocation sub-scenarios (Table 1). This report is the first in a series that will
eventually consider several more future scenarios involving significant changes to land use and
water management in the Wainono catchment. This report forms part of a multidisciplinary set of
reports that includes assessments of lowland and hill-fed streams, groundwater resources, and the
social, cultural and economic implications of scenarios for communities in the South Canterbury
Coastal Streams (SCCS) area. All these scenario assessments are designed to inform a communityinvolved process of developing water quantity and quality limits in the sub-regional section of the
proposed Land and Water Regional Plan (pLWRP) for Canterbury1 .
Table 1: Brief description of Scenario 1 and sub-scenarios 1a, 1b and 1c
This scenario considers what the future will look like until Hunter Downs Irrigation
(HDI) and Waihao Downs (WD) irrigation schemes are built, these being consented
schemes that will bring new (Waitaki) water into the SCCS area.
Scenario 1
Key assumptions include:
(pre HDI & WD)


Negligible new irrigated area is possible due to in-catchment water constraint
2
All land users operating at Good Management Practice (GMP )
Three sub-scenarios with different flow and allocation limits are considered as below.
Scenario 1a
Assumes the pLWRP minimum flow and allocation limits for streams, rivers and
3
groundwater within the SCCS area . These allocation limits are approximately the
current total allocation but no more.
Scenario 1b
Assumes alternative minimum flows that are generally higher and with smaller total
4
allocations to better meet the preferences of Manawhenua and to benefit
environmental values.
Scenario 1c
Assumes alternative minimum flows that are generally 25% lower than Scenario 1a,
but with the same allocation limits as Scenario 1a (i.e. current allocation), to provide
some increase in supply reliability to existing users but no new users.
1
See SCCS website for further details - South Canterbury Coastal Streams
GMP refers to good nutrient and irrigation management as assumed in the ‘Canterbury look up tables”.
Specifically this covers: use of nutrient budgets, application of fertiliser according to code of practice, stock
exclusion, efficient irrigation application (80 % application efficiency), and compliant effluent systems.
3
See Section 15 of the pLWRP - Proposed Canterbury Land & Water Regional Plan
4
The flow and allocation preferences of Manawhenua are expressed in a report (Tipa 2012) available on the
website ( http://ecan.govt.nz/publications/Reports/cultural-associations-flows-water-implications-wainonocatchment.pdf ). These are partly (but not entirely) based on recommendations in the proposed NES (i.e.
minimum flow 90%MALF; allocation 30% MALF) (MfE 2008).
2
A detailed description of Scenario 1 and key assumptions is provided on the project website1.
For Wainono Lagoon, the main relevant changes expected from the current situation to Scenario 1
are:

The Wainono Restoration Project5 is expected to partly reduce sediment load to the Lagoon by
reducing soil erosion loss at the farm level, and is also expected to enhance Wainono marginal
wetlands through willow control and strategic riparian planting.

Nitrogen (N) load to the Lagoon is expected to increase slightly (~10%) as a result of limited
intensification of land-use permitted under the pLWRP utilising the existing irrigated area in
the catchment. Phosphorus (P) load is expected to be not significantly changed.

Three sub-scenarios with different river flow and allocation limits for Wainono Lagoon
tributaries (Hook, Waihao and Merrys Stream) as described in Table 1.
Summary of Wainono values
Much has been written about Wainono Lagoon and its values. A recent review (Benn 2011)6 collates
the previous literature and summarises biological, physical, recreational, historical, social and
cultural values. Tipa (2012)7 has recently summarised water-dependent cultural values of the
Waihao-Wainono catchment, identified key issues and threats, and documented river flow
management preferences for manawhenua8.
In brief, Wainono Lagoon is a medium-sized (approximately 325 ha), turbid (murky – low clarity)
coastal lake which is usually about 1m deep and is separated from the sea by a gravel bar up to 8m
height. The Lagoon receives inflow from Waituna Stream, the Hook River, the northern Hook Beach
Drain, as well as reverse flow at times from the Waihao River via the Waihao Arm (also referred to
colloquially as the Dead Arm). The water can range from brackish to fresh depending on flow, level
and sea wave conditions. The Lagoon and its tributary catchments support numerous plant and
animal species including 26 fish species and over 100 bird species (Benn 2011). It features at times
shallow water aquatic weedbeds (macrophytes), flax, rush and sedge swamp, saline mudflats,
shingle beach ridge habitat, as well as willows and introduced grasses (Benn 2011; Golder 2012). The
Lagoon and its associated wetlands meet the criteria of internationally significant wetlands under
the Ramsar Wetland Convention although this status has not been formalised. The Lagoon and
wetlands have national status of Wildlife Refuge and Conservation Area.
To manawhenua, Wainono is a taonga (treasure) equivalent to Te Waihora (Lake Ellesmere) and
Wairewa (Lake Forsyth). It provides important habitat for waterfowl, migrating birds, coastal birds
and native fish, many of which are taonga species, in particular tuna (eels). To manawhenua, the
value of the Waihao-Wainono system as home to taonga species, and as a source of mahinga kai
cannot be overstated; the health of mahinga kai will be the ultimate indicator of the health of the
system (Tipa 2012). The treasured status is reflected in the designation of the Lagoon and the lower
reaches of its tributaries (Hook, Waituna and Waihao) as the “Waihao Mataitai Reserve” which
prohibits commercial fishing and promotes customary sustainable management. The Lagoon and
5
See SCCS website for further details - Wainono Lagoon
See http://ecan.govt.nz/publications/Plans/draft-instream-intrinsic-values-wainono-waihao-report.pdf
7
See http://ecan.govt.nz/publications/Reports/cultural-associations-flows-water-implications-wainonocatchment.pdf
8
Manawhenua are those who exercise customary authority or rangatiratanga over an area
6
surrounding area also has sites of considerable historical significance to both Maori and Europeans,
with numerous sites identified as wahi taonga (treasured places) and wahi tapu (sacred places). The
Lagoon and surrounds are also important to both local and regional communities for amenity and
recreation including bird watching, walking, picnicking, whitebaiting, eeling, floundering, water fowl
hunting and trout fishing (Benn 2011).
Summary of biophysical state under Scenario 1 (pre-HDI & WD)
Key biophysical aspects of the lake that influence the above values are summarised in Table 2 below.
The expected state for Scenario 1 (pre HDI & WD) is described in Table 2 with reference to current
conditions. An assessment is also made of the relative merits of Scenarios 1a, 1b and 1c for each
indicator (see three far right columns in Table 2). The relative assessment is made using a five-class
scale as shown in the coloured diagram below.
Where there is a clearly defined desired outcome, an
assessment is made of the likelihood that the outcome
will be achieved… (five-class scale)…
Where there is not a clearly defined desired outcome,
the assessment reflects only the relative merit of each
scenario… (five-class scale)…
Almost
certainly
Probably
Possibly
Unlikely
Highly
unlikely
Very high
(maximum)
High
Medium
Low
Very low
(minimum)
Table 2: Summary of expected biophysical state of Wainono Lagoon under Scenario 1 (pre-HDI & WD), and
assessment of the relative merits of Scenarios 1a, 1b and 1c against each biophysical indicator according to the
defined five-class scale. A narrative explanation of the difference between scenarios is shown in italics for each
indicator.
Indicator
Coastal morphology
Scenario 1 (pre-HDI &WD)
Wainono is a shallow coastal lake separated from the sea by a gravel
barrier built by wave action from sediment (gravels) carried northwards
along the coastline. The gravel barrier is migrating landwards at a long-term
rate of about 0.5m/year (Benn 2011) and this, amongst other factors,
continues to very gradually decrease the size and change the shape of the
Lagoon. While this natural coastal erosion process will continue, the Lagoon
and associated gravel barrier are expected to be permanent features of the
landscape, albeit slowly changing shape, for the foreseeable future relevant
for planning and management (B. Gabites and J. Cope, ECan, pers.comm,
and Gabites 2012).
There is no appreciable difference between scenarios for coastal processes.
Lake openings
Regular opening to the sea via the 100 year old Waihao Box (Figure 1)
allows the Lagoon water to flow to the sea, maintaining lake level typically
at average about 1m amsl although level varies within hours as the Box
alternately opens and constricts with wave-driven gravel. The Box provides
drainage and alleviates flooding of low lying land, as well as provides
passage for fish species that need to migrate to and from the sea at certain
times of the year to complete their life cycles (e.g. diadromous species such
as tuna (eels) and inanga (whitebait)). There seems to be general
agreement amongst local landowners, farmers, manawhenua, fishers and
recreationists that the Waihao Box has served this purpose very well and
there appears to be strong desire to retain the current system.
There is no appreciable difference between scenarios for Waihao Box
openings, although higher river minimum flows (Scenario 1b) could
arguably assist in a small way to keep the Box open.
1a
1b
1c
Lake level
Water level is typically around 1.0 m above msl but this fluctuates
depending on the size of inflows and the state of opening of the Box. When
the Box is closed water backs up the Waihao Arm and raises water level in
the Lagoon. The size of the Lagoon increases significantly at higher water
levels (e.g. ~420 ha at 1.5m amsl) (Benn 2011) and during floods can
inundate large areas of land to the north and south. Conversely when the
Box is open and inflows are small, the water level can drop dramatically
leaving exposed mudflats hundreds of metres from the normal water edge
vegetation line; this situation stresses most of the aquatic communities
although probably favours some specialised de-watering resilient species.
While level management at the Box is the primary driver of Lagoon level,
higher river minimum flows (Scenario 1b) would be better than lower
minimum flows under Scenario 1c for reducing low lake level stress on
Lagoon ecology.
Freshwater versus
brackish state
The Lagoon varies between a fresh and brackish state in both time and
space; the eastern edges near the beach barrier have higher salinity. The
main source of seawater is waves overtopping the barrier during storms
and barrier seepage during wave run-up at high tides, and occasionally
reverse flow through the Box and up the Waihao Arm (Goring 2006).
Lagoon communities are adapted to living in this variable environment;
some saline tolerant plant turf communities inhabit the eastern margins
and are of high ecological/botanical value (Boffa Miskell 2007).
There is no appreciable difference between scenarios for salinity state.
Macrophyte beds
Whilst macrophyte beds have been periodically present historically, the
Lagoon is now predominantly in a phytoplankton (algae) dominated state.
Some macrophytes have re-established at times (e.g. Ruppia sp. present in
summer 2012/13; M. Schallenberg pers. comm.) suggesting the Lagoon
may be a ‘flipping type’ lake that could periodically ‘flip’ between
macrophyte and phytoplankton states. This suggests there is potential for
the long-term return of macrophyte beds and this would improve water
clarity conditions in the vicinity of the beds (M. Schallenberg pers. comm.).
Species have in the past included Myriophyllum sp., Lilaeopsis
novaezelandiae, Rupia megacarpa and Ranunculus sp. (Tipa 2012). Some
local residents recall macrophytes being more widespread prior to the 1968
Wahine storm and consider that the storm permanently damaged Wainono
beds in a similar way to those damaged in Te Waihora.
There is little difference between scenarios for macrophyte beds, although
higher river minimum flows (Scenario 1b) would be better than lower
minimum flows under Scenario 1c for providing fresh water germination
conditions for Ruppia sp in spring.
Water quality (clarity &
colour)
The Lagoon is highly turbid, meaning it has low visual water clarity that
varies between about 10 cm to 40 cm (black disc), depending on the
amount of bed sediment re-suspension that varies with wind strength.
Water colour varies between a translucent green colour (32.5 Munsell
Units) during calm conditions (Figure 3), to a murky coffee colour (20 MU)
when fully mixed; this change can occur within minutes due to wind mixing
(Sutherland and Norton 2011). The greenness of the water is caused by
algae (phytoplankton); the brown coffee colour is caused by re-suspended
sediment and dominates colour during windy conditions.
There is little difference between scenarios 1a and 1c for water clarity and
colour. Scenario 1b with its higher minimum flows and smaller allocation
would slightly favour clearer water during calm, low lake level, but clarity
and colour would still be dominated by re-suspended bed sediment and
green algae most of the time.
Water quality
(sediment)
The Lagoon has historically (and still currently) received high loads of
sediment from erosion in the catchment, which has been exacerbated by
land vegetation clearance for agriculture. Sediment loads arrive
predominantly during floods, primarily from the Hook catchment (see
Figure 2). This has contributed to the accumulation of a thick layer of fine
sediment on the lake bed. This sediment re-suspends during common
(most days) windy conditions, creating the turbid (murky) conditions
described above, and contributing to algae (phytoplankton) growth by
contributing sediment-associated nutrients to the water column (e.g.
Schallenberg and Burns 2004).
The Wainono Restoration Project is targeting on-farm measures to reduce
erosion and sediment loss from the catchment through time. This is a
positive effect common for all scenarios; there is no appreciable difference
between scenarios for water suspended sediment or Lagoon bed
sedimentation.
Water quality
(nutrients, dissolved
oxygen, pH,
temperature)
The Lagoon is “hypertrophic”, meaning it has very high nutrient (N and P
concentrations and is highly productive with respect to phytoplankton
(algae) growth. The current annual average Trophic Level Index (TLI) is
approximately 6.5 (Sutherland and Norton 2011) (Figure 4), although this is
highly variable in time (Figure 5) and in different parts of the Lagoon. This
exceeds the maximum TLI of 6.0 set in the pLWRP outcomes for coastal
lakes. The historic (pre-European) trophic state of the lake is unknown but
may have been in the order of 4-5 (i.e. Meso- to Eutrophic). In simple terms
the high nutrient state means that the Lagoon is usually dominated by
phytoplankton (as opposed to macrophytes) and is subject to algae blooms
that can cause large fluctuations in dissolved oxygen (DO) and pH that can
cause stress to aquatic life (e.g. Sutherland and Norton (2011). Intense
blooms can increase pH and at pH greater than 9.2, dissolved reactive
phosphorus may be released from iron oxides in the Lagoon sediment
further stimulating algae blooms and significantly increasing the risk of
toxic cyanobacteria blooms (e.g. Gibbs and Norton 2013). In general, water
quality (e.g. nutrients N and P, DO, pH, temperature, salinity, turbidity,
colour, clarity, algae [chlorophyll a], TLI) is highly variable both temporally
and spatially in the Lagoon due to variable flow level, contaminant loads
from tributaries, in lake biological processes, wind-driven mixing, bed
sediment re-suspension and saline intrusions (Sutherland and Norton 2011)
There is little difference between scenarios 1a and 1c for water quality.
Scenario 1b with its higher minimum flows and smaller allocation would
afford more dilution of catchment contaminant loads and is therefore
slightly better for Lagoon water quality.
Cyanobacteria and/or
other toxic algae
The high nutrient state of the Lagoon (TLI 6.5) increases the risk of
cyanobacteria and/or other toxic algae blooms. Nuisance blooms have not
been commonly reported by the public but have been observed in the
short blind ‘Dead Arm’ coming off the Waihao Arm approximately 2km
south of the Wainono outlet (Sutherland and Norton 2011), and toxic
species (e.g. Planktothrix sp.) in the lagoon itself (Figure 6)(G. Clarke,
pers.comm). The level of risk of cyanobacteria bloom formation can be
estimated using a probability model (MfE 2009) based on key factors
influencing blooms (lake size, P and N concentrations, and wind speed
measured continuously at a recorder station on the lake). Wainono Lagoon
is currently at moderate risk using this method (Figure 7).
There is no appreciable difference between Scenarios 1a,b and c for toxic
bloom risk.
Fringing wetlands
Only modest remnants remain of the fringing wetlands that would once,
prior to draining the land for human occupation and agriculture, have
stretched to the south near the Waihao River and to the north near
Makikihi. Nonetheless the fringing wetlands that remain are highly valued
for intrinsic, scenic, and biodiversity value (Benn 2011). They also likely play
a role in metabolising some of the nutrient load entering the Lagoon from
neighbouring land. Wetland plant community types include ‘flax swamp’,
‘rush swamp’ and ‘sedge swamp’, and ‘mudflat’ (Benn 2011). Also
noteworthy are native wetland saltmarsh turf communities with high
ecological values (Boffa Miskell 2007; Benn 2011). Key threats include
invasive weeds (e.g. grey willow and reed canary grass), dewatering from
low tributary inflows and drainage, and damage from stock access.
There is limited difference between Scenarios 1a,b,c for fringing wetlands,
although higher river minimum flows (Scenario 1b) would be better than
lower minimum flows (Scenario 1c). Some improvement is expected
compared to current as a result of stock exclusion (rules of the pLWRP),
weed (willow) control and enhancement planting efforts under the
Wainono Restoration Project.
Biodiversity
Wainono Lagoon and its catchment support significant biodiversity
including fringing wetland plant communities (see description above),
sporadic macrophyte communities (see description above), 18 native fish
species including threatened species; Canterbury mudfish; longfin eel;
torrentfish, giant kokopu, inanga, lamprey and bluegill bully (Allibone et al.,
2010). Wainono is the largest coastal lagoon between Karitane and Te
Waihora (Ellesmere) and thus provides valuable feeding and roosting
habitat for many coastal bird species. At least 90 bird species have been
recorded at the Lagoon and the site is particularly important for a number
of nationally threatened species including: white heron, grey duck, royal
spoonbill, wrybill plover, black stilt, southern New Zealand dotterel,
Australasian bittern, black-billed gull and black fronted tern. Full species
lists (including aquatic invertebrates and phytoplankton) for the whole
catchment are provided in Benn (2011) and for the Lagoon itself in Golder
(2012).
For migratory fish species (e.g. eels, inanga, koaro, common bully and
torrentfish), Scenario 1b with its higher minimum flows and smaller
allocation would be significantly better than Scenario 1a, which is in turn
better than Scenario 1c.
Mataitai Reserve
(fisheries & other
mahinga kai)
The Mataitai Reserve was approved in 2012 and includes Wainono Lagoon
and that portion of the Waihao River catchment, Waituna Stream and Hook
River east of State Highway 1 (Figure)(Tipa 2012). Mahinga kai include
indigenous fish species, plants for eating and weaving, and birds including
eggs. Key species are tuna (eel), patiki (flounder) and inanga (whitebait) these fisheries have been subject to variable exploitation historically but
could recover under the Mataitai Reserve, provided habitat quality is
maintained and enhanced, and recruitment from the sea is maintained (i.e.
the Box). The tuna (eel) in particular has a special historic significance. It
was on the visit of the first recorded waka Uruao that the river was named
Waihao by the wife of Rakaihautu in recognition of the sweetness of the
hao eel, a significant species in the river (Tipa (2012).
“Whanau want to see increased populations of mahinga kai with fish
species (in particular tuna) having free passage throughout the system at all
Microbial quality for
recreation
stages of their life cycle. All species will be fit for use, and the river system
will be desirable for whanau to access and use. The health of mahinga kai
will be the ultimate indicator of the health of the system” (Tipa 2012).
Scenario 1b with its higher minimum flows and smaller allocation has been
specifically designed to reflect the flow preferences of manawhenua.
Scenario 1b would be significantly better than Scenario 1a, which is in turn
better than Scenario 1c for fisheries and other mahinga kai of the Mataitai
Reserve.
While the Lagoon is not popular for direct contact recreation, mahinga kai
gathering and waterfowl hunting bring people into contact with the water
and so microbial quality is relevant. Indicator microorganism (E.coli)
concentrations measured by ECan monthly from July 2007 to June 2009
th
satisfied the criteria for ‘Fair’ contact recreation grade (95 percentile =
410 E.coli/100mL). The Lagoon would rarely achieve the highest microbial
quality for contact recreation due to significant (and highly valued) bird
populations (see above). The risk of cyanobacteria blooms (see above and
Figure 7) is also relevant for recreation.
Some improvement in (stock-sourced) microbial contamination is expected
due to stock exclusion rules in the pLWRP. However it seems unlikely that
E.coli concentrations will reliably meet better than ‘Fair’ contact recreation
due to valued bird populations. There is negligible difference between
scenarios on this.
References
Allibone, R.; David, B.; Hitchmough, R.; Jellyman, D.; Ling, N.; Ravenscroft, P.; Waters, J. (2010).
Conservation status of New Zealand freshwater fish, 2009. New Zealand Journal of Marine and
Freshwater Research 44 (4):271-287.
Benn, J. (2011). Instream intrinsic values of the Wainono Lagoon-Waihao River catchment.
Draft/Living Document. Department of Conservation, Canterbury Conservancy, Christchurch,
New Zealand.
Gabites, B. (2012). A summary of Environment Canterbury’s coastal environment monitoring
programme for the coastline south of Timaru – 1977 to 2011. Environment Canterbury Report
No. R12/116 (ISBN 978-1-927234-10-5 (web)).
Gibbs, M., Norton, N. (2013) Te Waihora / Lake Ellesmere: Water Quality Mitigation and Restoration
Opportunities. NIWA Client Report CHC2012-138, prepared for Environment Canterbury, Draft
as at November 2012.
Golder Associates (2012). Ecological Flow Review. Waihao River and Wainono Lagoon Catchment.
Report Number 0978110112_001_R_Rev1. Submitted to Canterbury Regional Council, Christchurch.
Goring, D.G. (2006). Wainono Lagoon: Seawater Incursion. A report prepared for Environment
Canterbury by Mulgor Consulting Limited, May 2006.
Boffa Miskell (2007). Hunter Downs Irrigation: Terrestrial ecology, wetlands, and mudfish ecological
assessment. Prepared for Meridian Energy Limited by Boffa Miskell Limited (Report No.
C05244A), June 2007.
Ministry for the Environment and Ministry of Health (2009) New Zealand Guidelines for
Cyanobacteria in Recreational Fresh Waters – Interim Guidelines. Prepared for the Ministry for
the Environment and the Ministry of Health by S.A. Woods, D.P. Hamilton, W.J. Paul, K.A. Safi
& WM Williamson. Ministry for the Environment, Wellington.
MfE (2008). Proposed National Environmental Standard on Ecological Flows and Water Levels
(Discussion Document).Ministry for the Environment, Wellington.
Schallenberg, M., Burns, C.W. (2004). Effects of sediment resuspension on phytoplankton
production: teasing apart the influences of light, nutrients and algal entrainment. Freshwater
biology, 49, 143-159.
Sutherland, D., Norton, N. (2011) Assessment of augmentation of water flows in Wainono Lagoon.
NIWA Client Report CHC2011-043.
Tipa, G. (2012). Cultural Associations and their Flow and Water Management Implications for the
Waihao / Wainono Catchment. A Draft Working Document (not yet endorsed by Te Runanga o
Waihao) prepared by Tipa & Associates for Environment Canterbury, December 2012.
Figure 1. The Waihao Box facilitates flow from the Waihao-Wainono catchment draining to the sea.
The lower Waihao River (top right) joins the Waihao Arm (also known colloquially as the Dead Arm –
centre right) at the Waihao Box.
Figure 2. Photos illustrating the high sediment load plume from the Hook River entering Wainono
Lagoon (left) and sediment-laden water flowing from Wainono Lagoon down the Waihao Arm and
through the Box to the sea (right) during flood conditions in August 2012.
Figure 3: The Waihao Arm at Poingdestres Road, approximately 1 km downstream from the
Wainono outlet, showing the green colour of Wainono outflow water during calm conditions on the
Lagoon.
Figure 4. Illustration of Trophic Level Index (TLI) scale showing relative position of current state
(today) and Scenario 1 (pre-HDI & WD) versus estimated historic (pre-European) state and ECan
(pLWRP) outcome target.
Figure 5. Trophic Level Index (TLI) (moving annual mean) based on ECan lake edge measurements
since March 2000. Note this is based on a TLI(3) calculation using TP, TN and chlorophyll a but not
Secchi depth.
Figure 6. A surface scum algal bloom on Wainono Lagoon containing the potentially toxic
cyanobacteria (Planktothrix sp.). Photo taken from a helicopter during ECan surveys in March 2011.
Figure 7. Estimated level of risk of cyanobacteria bloom formation in Wainono Lagoon currently and
under Scenario 1, using a weighted probability function model described in the Interim New Zealand
Cyanobacteria Guidelines (MfE 2009). The risk is currently moderate (weighted probability 0.4 -0.6
which constitutes the Interim Guidelines ‘Alert level’) as assessed by Sutherland and Norton (2011).
Figure 8. Location of the Waihao Mataitai Reserve (red area and lines) that came into effect on 13
September 2012. Mataitai reserves can be established over traditional fishing grounds of special
importance to local Maori. Establishing a mataitai reserve does not prevent recreational fishing,
access to reserves, beaches or rivers, and does not change existing arrangements for access to
private land. Only commercial fishing is prohibited in a mataitai reserve (Tipa 2012).