201 



some supply of this nature is probably derived from the Ruahine at the sources 

 of the Oroua river. 



The whole area drained by the Manawatu being 1,171,200 acres, we find 

 the very large proportion of over 1,000,000 acres to be bush-covered, also there 

 is much flat country, so floods neither rise nor run off so quickly as in an open 

 country. The dense vegetation of the bush retains a large quantity of the rainfall, 

 and the ranges themselves are chiefly bush, and not very precipitous in general 

 character. 



For instance, on the Tirohanga hill-track, from the Manawatu to the 

 Forty-mile bush, passing over the Tararua range, after attaining on elevation of 

 about 1200 feet, we find nearly three miles flat before the ascent to the summit 

 is made ; several streams flow through this flat, and the ground has a thick, 

 spongy stratum on the surface of roots, moss, and soil. 



Similar comparatively level tracts, no doubt, exist at many places on the 

 hills at considerable elevations ; and thus the water falling on them by no 

 means necessarily finds its way rapidly to the lower levels and the main 

 river bed. From these causes more water niust be taken away by absorption 

 and evaporation, than at first might be supposed. 



One feature in the course of the Manawatu, as of other similar rivers, is 

 the numerous old water-courses abandoned by the river, and now forming semi- 

 circular shaped lagoons of uniform width in the flat bush country. 



These are found at intervals in a belt of half a mile to a mile and a half 

 in width, on both sides of the river. 



They have formed old river beds, cut through at the neck by the current, 

 and the ends silted up by the deposits brought down in floods. This process 

 still goes on, general extensive bends having been cut off within my own 

 knowledge, as at Raukawa, and near the mouth of the Tokomaru. 



A kind of balance is thus probably kept up between the speed and wearing- 

 power of the current, and the nature of the soil acted on by it, so that the 

 total length of the river course along its numerous windings, maintains a mean 

 from time to time ; the formation of a long bend by the stream eating into the 

 banks at one place, being counterbalanced by the cutting through the neck of 

 a peninsula at another. 



Some of these lagoons are over a mile long, and form fine sheets of 

 water. They are mostly filled in heavy freshets, by the water backing up the 

 stream flowing from their lower ends, and they, together with a large extent of 

 low land subject to floods, for some miles above the junction of the Oroua, act 

 as storing reservoirs for some of the surplus waters, as also do two large open 

 swampy tracts whose surface is about the level of high floods, — one on the 

 south side, called Makurerua, of some 15,000 acres, and the other lower 

 down on the north side, called Ohotuiti, of some 7000 acres, and both with 

 many shallow lagoons in their area. These are of rich soil, and when drained, of 

 which they are capable of being, will form important flax-growing and 

 meadow lands. 



The large extent of sand and gravel deposits also, no doubt, absorbs and 

 discharges gradually a large part of the rainfall, and of the waters brought 

 down by river floods. 



Differing from the Ruamakanga, the Manawatu is navigable for many 

 miles from its entrance, to vessels of six or eight feet draft of water, which the 

 bar at the mouth allows to enter, and the flood tide, when there is no fresh 

 in the river, gives an upward current for fifteen or sixteen miles from the 

 mouth. 



The course of the Oroua gives a good section of the land lying to the west 

 of the Ruahine range. For ten or fifteen miles of its lower course, it divides 

 the open sandy country of the coaat from the alluvial bush land, and here its 



