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Headwaters of the Ngermeskang River, Palau
Republic of Palau, Oceania, Ngeremlengui State
The Ngermeskang is the longes river in the Republic of Palau, with 20km of constant water flow emptying into Ngermendu Bay. Its headwaters lie in deeply-cut valleys, just below Palau’s highest mountain, Ngerchelchuus, between Ngeremlengui and Ngardmau State.
This is a pristine river, with little to no agricultural of domestic run-off, largely protected by national laws. It carves its way through the thick jungle, on a bed of volcanic gravel, smooth volcanic rocks, and fine red clay. It can only be accessed by foot, hiking down the steep jungle inhabited by reptiles, giant silk spiders, and fruit bat. The frequent rains can cause even the headwaters to dangerously swell in size and cause turbidity in the usually-clear waters (see my sad biotope underwater video). Even though saltwater crocodiles usually inhabit the lower reaches and mangrove areas, they have been observed in the deeper pools above falls, cascades, and rapids.
- Submitted by
- Rene Menz
- Approved by
- Greg Martin & Peter Unmack
- GPS
- 7.5006361, 134.5455170
- Geographical region
- Southeastern Asia
- Drainage Basin
- Ngermendu Bay
- River catchment
- Ngermeskang River
- Water body type
- hill-streams
- Water body name
- Ngermeskang
- Water body part
- Rapids
- Water body course
- Headwaters
- Water body: tributary of
- River
- Tributary name
- Ngermeskang
Videos above and below water
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Water Chemistry
Water information
- Water type
- fresh-water
- Water color
- Clear water
- Water transparency
- Medium
- Concentration of sediments
- Medium
- Water temperature
- 24-30 °C
- Water flow/curent
- Very strong
Chemical parameters
- pH
- 7.2
- Conductivity
- 400
- GH
- 7 mg/l
- dGH
- KH
- 7 mg/l
- dKH
- Dissolved Oxygen
- 7.5 %
Substrate in nature
- Sand
- Reddish
- Pebble/Gravel
- Orange
- Stone
- Mixed
- Stone form
- Irregular
- Silt/Mud
- Orange
- Leaves
- Many
- Driftwood
- Many
- Submerged terrestrial vegetation
- Yes
Aquatic Biotope
- Date of collecting
- 11/04/2020
- Collecting area
- Above waterfall
- Water depth
- 1,0m
- Air temperature
- 29 °C
- Sunlight
- Filtered/dappled sun
Environment
- Environment
- Untouched
- Surrounding area
Steep valley banks with dry pseudo-fern and Pandanus savannah drooping into the dense rainforest with too many species of plants to count, including numerous endemic orchids, trees, ferns, shrubs and mosses.
- Underwater landscape
Fishes:
- Stiphodon pelewensis (Sicydiinae) – Moderate Population
- Stiphodon percnopterygionus (Sicydiinae) – Scattered Population
- Sicyopus zosterophorus (Sicydiinae) – Dominant Population
- Smilosicyopus fehlmanni (Sicydiinae) – Moderate Population
- Redigobius bikolanus (Gobiidae) – Scattered Population
- Giuris margaritaceus (Eleotridae) – One Pair in every deeper pool between cascades and falls
- Anguilla marmorata (Anguillidae) – A population of frequent Visitors to the Headwaters
Shrimps:
- Caridina variabilis (Atyidae) – Very large and dense population
- Atyoida pilipes (Atyidae) – dense population in cascades and falls
- Macrobrachium rosenbergii (Palaemonidae) – Moderatly dense population in deeper pools between cascades and falls
- Macrobrachium sp. (Palaemonidae) – Scattered population in smaller pools between cascades and falls
Mollusks:
- Neritina pulligera (Neritidae) – Dense population
- Melanoides tuberculata (Thiaridae) – Abundant in the gravel and clay sediment
Aquatic plants/Mosses:
- ?Monosolenium tenerum (Monosoleniaceae) – Abundant on volcanic rocks submerged in shallow water
Shallow cascades with aufwuchs-covered rocks, from pebble to boulder size on volcanic gravel mixed with clay, interrupted by deeper pools with fallen leaves, vegetation and muddy sediment.
- Threats to ecology
Unlike this specific river in Palau, many similar waterway are threatened by agricultural, domestic and construction run-off. Many rivers have lost up to 70% of their biodiversity due to water quality degradation. In addition to the averse effects on freshwater aquatic inhabitants, which are poorly studied, this threatens the drinking water supply of Palau, which is completely dependent on surface water collection.
Riparian zone
- Trees near the aquatic habitat
-
Many - Pandaus aimerikiiensis, Semecarpus venosa, Pininga insignis, Stemonurus ammui, Phlegmariurus phlegmaria, Cyathea spp., Terminalia catappa
Bibliography
-
A Fieldguide to Native Trees of Palau
by Ann Hillman Kitalong, Robin Ann DeMeo and Tarita Holm
ISBN ISBN 978-982-98016-4-7 1
Comment by the expert
Greg Martin: Well researched.
Peter Unmack: I really good level of details across the categories.
