Official Journal of the Asia Oceania Geosciences Society (AOGS)
Table 1 Distinguishing attributes of River Styles in the Bislak Catchment
Valley setting | River Style | % Stream length | Channel planform | Geomorphic units | Bed material texture | Capacity for adjustment | Catchment area (km2) | Elevation (m) | Slope (m/m) | Valley width (m) | Stream power (W/m) |
|---|---|---|---|---|---|---|---|---|---|---|---|
Confined (> 85% of either channel margin abuts valley bottom margin) Total stream length: 57.2% | Confined, steep headwater, bedrock bed | 27.8 | Single thread, low sinuosity | Instream units: waterfalls, cascades, rapids, bedrock pools, riffles, bedrock outcrops No floodplain | Bedrock, boulder, cobble | Laterally stable, vertically stable | < 45 | 185–1455 | 0.01–1.04 | 10–30 | 95–5520 |
Confined, gorge, boulder bed | 23.6 | Single thread, low sinuosity | Instream units Cascades, bedrock steps, riffles, pools No floodplain | Bedrock, boulder, cobble | Laterally stable; limited potential for vertical adjustment | 2–115 | 140–780 | 0.008–0.24 | 15–50 | 155–8340 | |
Confined, occasional floodplain pockets, boulder bed | 5.8 | Single thread, low sinuosity | Instream units: rapids, pools, runs, boulder bars, benches, ledges Floodplain units: terrace | Bedrock, boulder, cobble | Limited potential for lateral adjustment (floodplain pockets); limited potential for vertical adjustment | 3–215 | 115–370 | 0.005–0.09 | 40–120 | 160–4305 | |
Partly confined (10–85% of either channel margin abuts valley bottom margin) Total stream length: 36.5% | Partly confined, bedrock margin-controlled discontinuous floodplain, cobble bed | 15.7 | Single thread, valley aligned | Instream units: pools, riffles, runs, compound bank-attached bars, mid-channel bars, benches, ledges Floodplain units: terrace, chute channel | Bedrock, boulder, cobble, gravel, sand | Limited potential for lateral adjustment (floodplain); limited potential for vertical adjustment | 10–255 | 75–210 | 0.002–0.03 | 110–420 | 160–2515 |
Partly confined, planform-controlled, low sinuosity discontinuous floodplain, gravel bed | 1.7 | Single thread, low sinuosity | Instream: pools, riffles, runs, compound bank-attached bars, mid-channel bars, benches, ledges Floodplain units: terrace | Boulder, cobble, gravel, sand | Moderate potential for lateral adjustment (floodplain); moderate potential for vertical adjustment (floodplain stripping and reworking) | 2–10 | 130–200 | 0.009–0.03 | 300–1450 | 75–220 | |
Partly confined, planform-controlled wandering, discontinuous floodplain, cobble bed | 19.1 | Single thread, low sinuosity | Instream units: pools, riffles, runs, benches, ledges Floodplain units: floodplain, terrace, floodchannels, chute channels | Boulder, cobble, gravel, sand | Moderate potential for lateral adjustment (floodplain); moderate potential for vertical adjustment (floodplain stripping and reworking) | 20–550 | 25–100 | 0.002 | 80–200 | 85–2640 | |
Laterally unconfined (< 10% of either channel margin abuts valley bottom margin) Total stream length: 6.3% | Laterally unconfined, continuous channel, braided, gravel bed | 5.1 | Multiple threads, low sinuosity | Instream units: pools, riffles, runs, compound bank-attached bars, compound islands, benches, ledges Floodplain units: paleochannel, chute channels, floodchannels | Cobble, gravel, sand | Large potential for lateral adjustment (floodplain; but more limited where anthropogenically confined); moderate potential for vertical adjustment (aggradation/degradation) | 550–585 | 2–25 | < 0.001–0.002 | 1200–3200 | 0–2270 |
Laterally unconfined, continuous channel, deltaic, sand bed | 1.2 | Multiple threads, variable sinuosity | Instream units: compound bank-attached bars, compound islands Floodplain units: paleochannel, anabranches, floodchannels and floodrunners, backswamp, chute channel, levee | Gravel, sand, silt, clay | Moderate potential for lateral adjustment (floodplain more cohesive, but opportunities for avulsion); limited potential for vertical adjustment | > 585 | 0.2–2 | < 0.001 | > 2000 | N/A |