Wave Swash Research Articles

A coupled-mode technique for the transformation of ship-generated waves over variable bathymetry regions

In the present work, a coupled-mode technique is applied to the transformation of ship's waves over variable bathymetry regions, characterised by parallel depth-contours, without any mild-slope assumption. This method can be used, in conjunction with ship's near-field wave data in deep water or in constant-depth, as obtained by the application of modern (linearised or non-linear) ship computational fluid dynamic (CFD) codes, or experimental measurements, to support the study of wave wash generated by fast ships and its effects on the nearshore/coastal environment. Under the assumption that the ship's track is straight and parallel to the depth-contours, and relatively far from the bottom irregularity, the problem of propagation–refraction–diffraction of ship-generated waves in a coastal environment is efficiently treated in the frequency domain, by applying the consistent coupled-mode model developed by Athanassoulis and Belibassakis [J. Fluid Mech. 1999;389] to the calculation of the transfer function enabling the pointwise transformation of ship-wave spectra over the variable bathymetry region. Numerical results are presented for simplified ship-wave systems, obtained by the superposition of source–sink Havelock singularities simulating the basic features of the ship's wave pattern. The spatial evolution of the ship-wave system is examined over a smooth but steep shoal, resembling coastal environments, both in the subcritical and in the supercritical case. Since any ship free-wave system, either in deep water or in finite depth, can be adequately modelled by wavecut analysis and suitable distribution of Havelock singularities e.g. as presented by Scrags [21st Int. Conf. Offshore Mech. Arctic Eng., OMAE2002, Oslo, Norway, June 2002], the present method, in conjunction with ship CFD codes, supports the prediction of ship wash and its impact on coastal areas, including the effects of steep sloping-bed parts.

Helpful habitant or pernicious passenger: interactions between an infaunal bivalve, an epifaunal hydroid and three potential predators.

The importance of positive interspecific interactions within physically stressful habitats has received increased attention from community ecologists. The exposed sandy beach is an example of a physically rigorous environment where biological interactions have long been considered insignificant. We examined the interaction between the infaunal clam, Donax variabilis, and the hydroid, Lovenella gracilis, on exposed sandy beaches in North Carolina. Epibiotic occupation of Donax by hydroids has been repeatedly observed on ocean beaches but rarely investigated. By providing a stable substrate for attachment, the clam facilitates the persistence of the hydroid in the intertidal beach; however, benefits or costs experienced by the host as a result of this association are unknown. By exposing clams with and without hydroid colonies to multiple types of clam predators, we tested the effectiveness of the hydroid, which possesses stinging nematocysts, in defending its host. The hydroid defended the clam against one common predator, the Florida pompano ( Trachinotus carolinus). Against speckled crabs ( Arenaeus cribrarius) and ghost crabs ( Ocypode quadrata), however, the hydroid offered no protection for its host and instead facilitated predation. The epibiotic hydroid, which projects above the surface of the sand, allowed the crabs to more readily detect clams below the surface. In the field, we evaluated the effect of the hydroid on the tidally synchronized migrations and burrowing speed of the clam. The hydroid, which can form large colonies on the posterior end of the clam, had no effect on Donax burrowing speed, but did reduce the speed of transport of clams by wave swash. Depending on relative predation pressure, the occupation of D. variabilis by L. gracilis can alternately be characterized as beneficial or detrimental to the host.

Effects of motorised boat passes on the time budgets of New Zealand dabchick, Poliocephalus rufopectus

New Zealand dabchicks, Poliocephalus rufopectus, are small grebes restricted to the North Island of New Zealand; with a total population of only ~1200–1500 birds, they are classed as endangered. We conducted experiments to examine the effects of boat passes of different speeds and frequencies on the time budgets of the New Zealand dabchick. We also examined whether New Zealand dabchicks became habituated to boat passes. We found that a single boat pass caused a significant short-term change in New Zealand dabchick behaviour compared with pre–boat pass patterns. This change in behaviour was more pronounced when the frequency of boat passes was higher, and may impose energetic constraints on New Zealand dabchicks. Differences between behaviour before and after the boat pass were no longer evident 15 minutes after the boat pass. We found no significant effects of boat speed (5 v. 10 knots) on the behaviour of New Zealand dabchicks. There was evidence of habituation to boat traffic in high-use recreational sites. Further studies are required to investigate the influence of other human activities and the influence that boat and wave wash have on the nesting and breeding success of the New Zealand dabchick.

Predicting the crest height of a gravel beach

The beach crest is a common morphological feature formed by the deposition of sediment carried up-slope by wave swash. The elevation to which waves can pile gravel is a function of the size and density of the material relative to the hydraulic components of swash velocity, wave frequency and runup height. Two equations ((17) and (21)) that predict the height of the beach crest to the wave forces and the beach material are derived. The first derivation compares the wave force acting to move a stone up the beach face with a weight force acting to hold the stone in place. The second derivation relates the potential energy per unit area of the beach crest to the total wave energy that lifted and deposited the material above a given sea-level datum. As a test of the derived equations, the actual crest height of one natural gravel beach was accurately estimated by both equations derived. Further research and testing on other natural beaches are needed to fully verify Eqs. (17) and (21). A comparison of other equations (Eqs. (2), (3) and (4)) that predict crest height is also made. The poor fit of the other equations are a result of using values for the coefficients that were established in wave tank experiments. Another shortcoming of Eqs. (3) and (4) is that they do not include variables related to the beach material. Hence, they predict that all particle sizes from sand to boulders would be piled to the same elevation by the same wave forcing. Eq. (2) includes a particle size variable but predicts increasingly higher beach crests for larger particles. More realistic results for all three equations (Eqs. (2), (3) and (4)) would be expected with field-tested values for the coefficients, but a range in values for each different beach would be necessary. The advantage of Eqs. (17) and (21) is that equations are not dependent on coefficients whose values come from correlation with other data sets.

In situ measures of spawning synchrony and fertilization success in an intertidal, free-spawning invertebrate

The rocky intertidal zone has the potential to be one of the harshest environments for free-spawning organisms, but empirical data on fertilization success are scarce. Here, I report on an intertidal, solitary ascidian, Pyura stolonifera, which was observed to spawn at low tide. At a scale likely to be most important to gametes (metres, duration of tide), approximately 30% of individuals in the population were spawning synchronously. Spawned gametes remained in a viscous matrix and this appeared to minimise their dilution. Fertilization success varied greatly among individuals (0 to 92%) and was related to the distance to the nearest neighbouring spawner. Occasional wave wash facilitated the movement of sperm between spawners. Fertilization success in some individuals was limited by the scarcity of sperm whilst the experimental addition of sperm did not increase success in others.

Diabetes Bars and Beverages: The Benefits and the Controversies

The couple in the advertisement, a pair of retirees, is enjoying a vigorous outing on the beach. They walk briskly through the surf as waves roll in over their feet. We find out that the couple faces having diabetes. However, they use a special food product the ad tells us is “designed for people with diabetes.” The product helps them control their blood glucose and maintain optimal health. The scene is hopeful and reassuring that, with the help of this product, it is possible to have good diabetes control, look good, and feel great and to do so without an overwhelming amount of effort. This ad was no doubt produced to capture the attention of the burgeoning market of individuals with diabetes—16 million adults in the United States.1 Through visual suggestion, the ad offers an important message about positive lifestyle choices, such as doing moderate physical activity, eating right, maintaining a healthy weight, managing stress, and enjoying life. However, at the end of the scene, a significant oversight becomes obvious. When the waves wash back, we see the couple, otherwise seemingly doing things right, walking along barefooted , thereby leaving themselves vulnerable to potentially undesirable consequences. The food item advertised is one of a growing number of products known as “functional” or “medical” foods that are formulated to address the nutrition concerns of people with diabetes or abnormal glucose tolerance. These products, in the form of beverages and snack bars, are developed to meet society’s demand for convenience, portability, and good taste. At the same time, they are promoted as healthy foods that help people with diabetes manage their disease by improving glycemic control and lowering risk factors for long-term complications, especially cardiovascular disease. This article offers information about currently available diabetes bars and beverages, the research that has …

Metapopulation dynamics of Tigriopus brevicornis (Harpacticoida) in intertidal rock pools

Rock pools above the level of mean high tide are frequently occupied by harpacticoid copepods of the genus Tigriopus. The network of populations in separate pools can be viewed as a metapopulation. However, in a dynamic environment subject to rainfall, tidal flushing and wave wash, there may be no particular structure to rock pool populations. Time series samples from pools at different levels on the shore were used to test for the presence of separate local population dynam- ics of T. brevicornis (Muller). Sample counts taken from the same pool 2 d apart showed autocorrela- tion in pools from the upper and middle of the range occupied by T. brevicornis. However, the dynamics of different pools were not strongly correlated. For counts of copepodites and adults, the degree of coupling between pools was a function of distance. The height of high tide affected counts in pools. Copepodite and adult numbers fell in pools at the lower end of the species range during spring tides. In comparison, there were spring-tide-associated increases in copepodite and adult numbers in pools above the mean height of high tide. Persistence of populations on the shore may therefore be aided by upshore movement of copepodites and adults during spring tides. Multivariate analysis of stage structure in pools suggested that pools acted as individual systems over a period of 31 d. The results indicate a degree of local population dynamics in separate pools, but the inferred metapopulation structure does not follow the classical model, since extinction events were rare in pools above the mean high tide level.

Distribution of macroinvertebrates in relation to physical and biological variables in the littoral zone of nine New Zealand lakes

Macroinvertebrates play a key role in the littoral zone of lakes. Macroinvertebrate community composition is closely linked to habitat conditions. To date, there have been few attempts to relate macroinvertebrates to habitat factors in lakes. In this study, nine mainly oligotrophic lakes from throughout New Zealand were surveyed for macroinvertebrates. The lakes were selected to represent a range of suspended sediment loading and lake level regimes. Within each lake, several sites were selected to provide a range of exposure to wave action. A multiple regression approach was taken to relate macroinvertebrate community composition and habitat characteristics. The results of the analysis suggest that the littoral zone of the lakes we studied could be divided into four general habitats. The first is the wave wash zone characterised by coarse substrates and macroinvertebrate taxa usually associated with lotic environments, such as Ephemeroptera and Plecoptera. The second habitat is associated with macrophytes and is limited at the top by wave action and at depth by light attenuation. In this zone, the snail Potamopyrgus antipodarum is dominant, along with Trichoptera and Odonata. At the base of the macrophytes is the detrital habitat characterised by fine, organic rich sediments and dominated by chironomids, oligochaetes and Trichoptera. At depths below the macrophyte zone, fine sediments are found, and bivalves such as the freshwater mussel Hyridella menziesi are common. While macroinvertebrate abundance can be highly variable, some general predictions of community structure can be made based on a few key environmental factors. Abundance of snails Odonata and Trichoptera was positively related to macrophyte biomass. Some macroinvertebrate groups such as oligochaetes, chironomids, snails and bivalves were more common in fine substrates, while Ephemeroptera were characteristic of coarse substrates. Detrital biomass was important for most of the macroinvertebrate groups studied showing a positive relationship for oligochaetes and Trichoptera and a negative relationship for Ephemeroptera and Plecoptera.

DEVELOPMENT OF A SURFACE STERILIZATION SYSTEM COMBINED WITH A WASHING PROCESS TECHNOLOGY FOR LEAFY LETTUCE

Various washing systems combined with chlorinated water, ozonated water, ultrasonic waves, and spray washing were developed to increase the efficiency of surface sterilization of leafy lettuce. Leafy lettuce treated with 100 mg.L -1 , 150 mg.L -1 and 200 mg.L -1 chlorinated water for 20 min decreased microbial load by 90%-99%. Samples treated with ozonated water (1.0-1.5 mg.L -1 ) at 4°C for 30 min decreased microbial load by 99%. Ozone treatment for 60 min resulted in 99.9% reduction in coliforms. The solubility of ozone increased with the reduction in water temperature and is very compatible with a hydrocooling system. Ultrasonic wave, vortex and spray washing techniques decreased microbial load, however none achieved greater than a 90% reduction.

Foraging Strategies of the Galapagos Marine Iguana (Amblyrhynchus Cristatus) : Adapting Behavioral Rules To Ontogenetic Size Change

[Ontogenetic development in reptiles entails major changes in size-related foraging options. We studied the changes in foraging behavior of marine iguanas. In this species, size increases about twenty- to hundredfold from hatching to full adult size. The foraging strategy of marine iguanas was studied at Miedo on Santa Fe Island in the Galapagos archipelago. During low tide, large marine iguanas (>250 mm snout vent length (SVL)) foraged more in the lower intertidal than small ones ( 250 mm snout vent length (SVL)) foraged more in the lower intertidal than small ones (<250 mm SVL) which preferred the upper intertidal with higher temperatures and less frequent wave washing. Animals usually returned to the same foraging site day after day and had lower food intake after changing their foraging site. Feeding accounted for 60% of the time spent in the intertidal. Smaller animals fed every day, larger ones only every other day. Smaller individuals shuttled faster between foraging and basking sites than larger ones. Total feeding time per day was, however, the same for both size classes. At neap tides (= high water level at low tide) animals had shorter foraging bouts than at spring tides with much lower water levels at peak low tide. Length of feeding bouts depended most on wave action, time of low tide (during the daylight period), and body mass of an animal. Small animals fed significantly less at higher than at lower wave activities. All animals on Santa Fe spent more time feeding in the intertidal than in the subtidal. Only large males additionally foraged subtidally and the more so the bigger they were. During the reproductive season, territorial males were less likely to go foraging, but when feeding, territorials fed more subtidally than nonterritorials, went foraging earlier, and spent less time foraging in the IT than nonterritorials. Ability to resist wave drag increased with body size but did not decrease at lower body temperature, whereas running speed did so significantly. Bite frequency during foraging also decreased with decreasing body temperature and smaller, younger animals had higher bite rates than older, bigger ones. White-painted animals rewarmed slower than naturally black ones and partially compensated for this by shortening foraging bouts but increasing their number. The observed age-related changes in foraging behavior can be explained by postulating a rule of the form 'forage while warm and warm up when getting inefficient at grazing'. Of course, animals will also stop feeding should the stomach be filled before the end of the low tide cycle. To explain age- and motivation-related differences in foraging behavior, the only change that needs to be postulated is in the thresholds of body temperature inducing switches from foraging to warming-up and back. These changes are adaptive responses to size-related changes in costs and benefits of foraging in a cool, wavewashed environment.]

The low competitive ability of Canada's Atlantic coastal plain shoreline flora: Implications for conservation

With over 22 nationally or globally significant Atlantic coastal plain taxa in Canada, there is a need for broadly applicable management strategies and the general models that make such strategies possible. Coastal plain species occur primarily in infertile areas and/or on shorelines exposed to wave wash or seasonal flooding. Experiments show that coastal plain species are restricted to such areas by the inability to compete with competitively superior species that occupy fertile, undisturbed areas. Coastal plain plants almost always co-occur with either isoetids or carnivorous species, two well-known stress-tolerant groups of plants, indicating that coastal plain species are also stress tolerators. The rarity of coastal plain species is a consequence of limited habitat with low competition intensity, so conservation strategies should emphasize the preservation of remaining habitat and the maintenance of existing levels of infertility, flooding and exposure.

Backwash-and-swash-oriented current crescents: indicators of beach slope, current direction and environment

Backwash-and-swash-oriented current crescents, which are confined to the swash zone of beach environments, are reported, with their detailed morphology and formation mechanism, from the siliciclastic fine sandy beaches of Sagar Island and Lower Long Sand, two tidal islands of the Ganga estuary, northeast India.Morphologically, the swash-oriented arms of these current crescents are shorter and less prominent than the backwash-oriented arms. The shorter arms open landward whereas the longer arms open seaward. They generally form around obstacles like armoured mud balls, polychaete tubes, tussocks etc. which are partially set in a scour implying greater anchoring or a semipermanent nature. These current crescents occur on fine to very find sandy beaches (Mz = 2.9 to 3.1 Φ) with a beach slopes of 1:50 to 1:90 (1.4-0.7°). They are very commonly associated with current lineations. The arms of crescents parallel current lineations and are at right angles to the shoreline.In contrast, ordinary backwash-oriented current crescents form on steeper beach slopes, 1:9 to 1:25 (6−3°), in fine to medium sand(Mz = 1.8 to 2 Φ). They occur around tiny obstacles which are easily swept away by wave swash and backwash.

Coastal bench formation at Hanauma Bay, Oahu, Hawaii

A coastal bench that developed from 1 to 6 m above sea level in basaltic tuff at Hanauma Bay conforms to the upper limit of wetting by wave wash at high tides associated with present sea level; it does not constitute evidence for a recent Holocene highstand on Oahu. Variations in bench width and elevation are related to differences both in exposure to waves and in exposure to daily heating and drying of the cliff behind the bench. Salt weathering of the sort usually invoked to explain weathering effects in deserts is a major factor in the retreat of the cliff and the consequent formation of the bench. The waves do not cut the bench but, instead, by daily wetting, protect it from desiccation. The bench forms as a result of the disintegration and retreat of the unprotected cliff. The same process can satisfactorily explain the formation of Koko Bench, presently submerged at -5 m along the north shore of Hanauma Bay. Use of similar benches as geological indicators of past sea levels requires a detailed understanding of the coastal setting and exposure to waves, and the different responses of specific rock types at and above the air-sea interface.

Irregular Wave Setup and Run‐up on Beaches

The one-dimensional equations of mass, momentum, and energy are derived from the two-dimensional continuity and Reynolds equations in order to elucidate the approximations involved in these one-dimensional equations, which have been used previously to predict normally incident wave motions on coastal structures and beaches. The numerical model based on these equations is compared qualitatively with the wave setup and swash statistics on a moderately steep beach with a nearshore bar. The numerical model is shown to predict the irregular wave transformation and swash oscillation on the barred beach, at least qualitatively. The computed setup and swash heights are found to follow the lower bound of the scattered data points partly because of the neglect of the longshore variability on the natural beach and low-frequency components in the specified incident wave train. A more quantitative comparison is also made with the spectrum of the shoreline oscillation measured on a 1:20 plane beach, for which the corresponding wave spectrum was given. The numerical model is shown to predict the dominant low-frequency components of the measured spectrum fairly well.

Current crescents formed by marine algae (Valonia sp.): a new record of obstacle marks lacking preservation of obstacles

Obstacle marks, formed around non-permanent tools, commonly occur on the beach faces of Lower Long Sand Island and Sagar Island, two tidal islands in the Ganga River estuary, India. The marine globose algae, Valonia sp., which bloom profusely in the waters of the Bay of Bengal during winter, are deposited on beach faces after being carried by wave swash, and then act as impermeable obstacles in the path of wave backwash. This creates around the globose algal bodies U-shaped or crescentic marks 2–3 cm in width with arms 1–3 cm in length. The globose vesicles are soon broken up by external forces or by forces of surface tension, leaving crescentic marks around a circular filamentous impression. The crescents always open toward the direction of wave backwash. These structures may prove useful not only for interpreting the palaeoslope and palaeocurrent directions but also for recognizing the palaeoecology.

The conservation and management of a threatened coastal plain plant community in Eastern North America (Nova Scotia, Canada)

The distribution of wetland plant species was described along a standing crop and litter gradient at Wilsons Lake, a nationally significant wetland habitat in Nova Scotia, Canada. Disjunct populations of rare and endangered Atlantic coastal plain species were found to contribute most to total standing crop when biomass was low. A similar distribution for isoetids, a group of stress-tolerant shoreline plants, indicates that low biomass areas are also infertile. The rarity of the coastal plain flora seems to be related to the lack of low biomass/infertile shorelines within the flora's geographical range. Conservation of the flora therefore involves preserving the remaining habitat and maintaining the current processes of flooding, wave wash, and ice scour that are maintaining infertility.

The deglaciation sea level and the marine limit in the Laholm—Halmstad area, Sweden

Abstract Differences in sea level determinations for the Laholm-Halmstad area are up to 20 metres. This is mainly due to the existence of two different sea levels, a lower, older deglaciation level and a higher, younger transgressive ML level. The topset/foreset contact in ice-marginal glaciofluvial deposit is used as a reference plane, RP, from which sea level at the time of their deposition is deduced. This is based upon the assumption that the RP is situated between 0.5 and 4 m below the mean sea level. The results of this study seem to support this assumption, however, a systematic study of variations in the RP levels within individual deposits is necessary to test this assumption. The deglaciation sea level is deduced to be +51 to +52 m in the southern part of the area and +55 to +56 m in the northern part. The ML values, based upon the limit of wave washing, are compiled from the literature and indicate a ML of +60 to +61 m in the south and +66 to +69 m in the north. A hiatus, representing a subaeri...

Vesicular-arbuscular mycorrhizas in submerged aquatic plants of New Zealand

Vesicular-arbuscular mycorrhizas were found in 22 submerged water-plant species. The existence of mycorrhizal infections in permanently submerged plants was established with records down to 6.0 m depth of water in one lake, and at 2–3 m depth in two other lakes. These depths were lower than the minimum water levels ever recorded for these lakes. Mycorrhizal plants were also found in 17 other lakes around New Zealand. Infection levels showed a general decline with increasing water depth. No relationship was established between the incidence of mycorrhizal infection and the trophic status of the lakes sampled. An association was observed between mycorrhizal infection, the degree of root hair development and the growth form of aquatic plants. High levels of infection were often found in shallow water plants, particularly those without root hairs or with noticeably sparse root hair growth. Most of these plants were also low-growing, shallow rooted plants. Plants with abundant root hairs were either not infected or tended to have low levels of infection. Most of these plants were tall-growing, deeper rooted plants and normally grow in deeper water. Possible explanations for the observed associations are suggested including high absorptive shoot surfaces for tall plants making them less dependent on roots for nutrients, and the probable existence of aerobic substrates in shallow water sandy substrates of the wave wash zone in lakes which could cause soluble phosphorus levels to be low in the rhizosphere of plants growing in this zone.

BEACH FILL BY TURNING THE COURSE OF SANDBARS

The paper discribes the littoral drift along the Eastfrisian Islands. The inlets between the islands are crossed by offshore bars which migrate round the deep channel of the inlet northwards on a bow. Their point of approaching the next island scatters. That causes periods of accretion during the approach of the bars on the beach and of erosion in certain beach sections without bar approach and sand supply. When an offshore bar approaches a beach it moves a swash channel ahead as a rule. This causes a rising beach erosion by currents and wave wash and hinders the settling of the bar on that beach section. This paper reports a field study on influencing the migration of a bar by building a sand dam through such a swash channel. It was intended of feed the eroded section of the beach by the steered approach of the bar. The accretion by the desired approach of the bar on the eroded beach section was higher than expected and measured more than 270 m'/m.

Controls on Tadpole Populations of the Chorus Frog

In Isle Royale National Park, Michigan, the larval distribution and abundance of the chorus frog, Pseudacris triseriata, results from an interaction of three factors: persistence of the larval habitat, size-specific predation, and density dependent competition for food. The chorus frog is widespread in eastern North America. On Isle Royale, it breeds on rocky shorelines exposed to storm waves from Lake Superior. The shores of Lake Superior slope gently into the lake and are covered with numerous small pools, filled by rain or waves. Chorus frogs breed in the pools in May and June. Metamorphosis begins in early July and extends at least into September. The time from egg-laying to metamorphosis of the first tadpole in any given pond is long, ranging from 55 to 83 days. Due to desiccation and wave wash from the lake, the persistence of pools is highly variable. Small pools and pools next to the lake are ephemeral, whereas large pools next to the forest are permanent, and many of the pools last less than the time required for the tadpoles to attain metamorphosis (Figure 1). Variation in pool persistence is a major source of tadpole mortality. Although chorus frogs lay eggs in pools with a wide range of persistence, tadpoles in ephemeral pools survive poorly. However, permanent pools also show considerable variation in tadpole survivorship (Figure 2); some of this is due to predation. Dragonfly nymphs (Aeschnidae) are the only predators sufficiently large and abundant to prey heavily on chorus frog tadpoles. Dragonflies live in large pools near the forest edge, but are absent from the small pools, presumably because they require more than one season to develop. The result of this pattern is that most tadpoles do not coexist with dragonfly nymphs; in the few pools with both species, the tadpoles occur only at low densities. The infrequent occurrence of tadpoles on the upper shore suggests that dragonflies prevent chorus frog tadpoles from surviving in the permanent pools. To test this idea, I carried out a simple addition and removal experiment. I located four large pools near the forest edge. Two of these, somewhat lower on the shore, contained tadpoles but no dragonflies; the other two contained dragonflies but no tadpoles. I removed all tadpoles from the pools, then removed dragonflies from one of the upper pools and added dragonflies to one of the lower pools. Tadpoles were then reintroduced to all pools at equal initial densities. The effect of dragonfly addition on tadpole survivorship was dramatic; all tadpoles were quickly killed by the dragonflies. Tadpoles grew rapidly in the upper pool where the dragonflies had been removed, indicating that conditions in pools ordiCONTOURS IN DAYS