Hawaii and the Pacific Islands - U.S. Army Corps of Engineers

ERDC/EL TR-12-5viiFigure 22. Stratified layers in loamy material. Scale is in inches on the right. ................................... 53Figure 23. Stratified layers in sandy material. Scale is in inches on the right side of ruler. .............. 53Figure 24. This mucky modified, sandy surface layer is approximately 3 in. (7.5 cm) thick.Scale in inches on the right side of ruler. ............................................................................................... 54Figure 25. A wetland with surface water present, Waipi‘o Valley, Hawai‘i. ......................................... 60Figure 26. High water table observed in a soil pit. ................................................................................ 61Figure 27. Water glistens on the surface of a saturated soil sample. ................................................. 62Figure 28. Water marks on rocks in a seasonally ponded depression. .............................................. 63Figure 29. Water marks (dark stains) on trees in a seasonally inundated wetland. The topof one water mark is indicated by the arrow. ......................................................................................... 64Figure 30. Silt deposit left after a recent high-water event forms a tan coating on thesetree trunks. ................................................................................................................................................ 64Figure 31. Drift material caught on a fence and in low vegetation in a coastal wetland. ................. 65Figure 32. Algal mat in a recently ponded depression, Kawainui Marsh, O‘ahu. .............................. 66Figure 33. Drying algal mat surrounding a ponded depression near the Saddle Road,Island of Hawai‘i. ...................................................................................................................................... 67Figure 34. Dried crust of blue-green algae that has cracked and curled. .......................................... 67Figure 35. Iron sheen on the water surface may be deposited as an orange or yellow crustafter dewatering. ...................................................................................................................................... 68Figure 36. Iron deposit (reddish area) in a taro patch. ......................................................................... 69Figure 37. Aerial photograph showing inundation within an emergent wetland in theKo‘olau Mountains on O‘ahu. ................................................................................................................. 69Figure 38. Water-stained leaves in a coastal wetland. ......................................................................... 71Figure 39. Water-stained hau (Hibiscus tiliaceus) leaves at Kawainui Marsh, O‘ahu. ...................... 71Figure 40. Remains of fiddler crabs (Uca spp.) in a coastal wetland. Fiddler crabs arefound in American Samoa, Guam, and the Northern Mariana Islands, and are not knownto occur in the Hawaiian Islands. ............................................................................................................ 72Figure 41. Aquatic snails in a coastal wetland. ..................................................................................... 73Figure 42. Dead fish in a dried pool near Wai‘anae, O‘ahu. ................................................................ 73Figure 43. Cluster of tilapia nests in a shallow pond. ............................................................................74Figure 44. Tilapia nest along the fringe of a drying pool near Wai‘anae, O‘ahu. ............................... 75Figure 45. Surface soil cracks (and drift material) in a coastal wetland. ........................................... 76Figure 46. A sparsely vegetated depression in Batis-dominated coastal flats, northernO‘ahu. ........................................................................................................................................................ 77Figure 47. Vegetation bent over in the direction of water flow across a stream terrace. .................. 78Figure 48. Iron-oxide plaque (orange coating) on a living root. Iron also coats the channelor pore from which the root was removed. ............................................................................................ 79Figure 49. Soil with oxidized rhizospheres surrounding many fine roots. ........................................... 80Figure 50. When alpha, alpha-dipyridyl is applied to a soil containing reduced iron, apositive reaction is indicated by a pink or red coloration to the treated area. ................................... 81Figure 51. Redox concentrations in the tilled surface layer of a recently cultivated soil. .................. 82Figure 52. Fiddler crab burrows and excavated soil. ............................................................................ 84Figure 53. Salt deposits (light-colored areas) on coastal flats near Wai‘anae, O‘ahu. ..................... 85