the olifants river's largest tributaries are the letaba river and the steelpoort river known as tubatse river. other tributaries are the tongwane, blyde, moses, spekboom, timbavati, nkumpi, ga-selati, klaserie, makhutswi, mohlapitse river, lepellane river, mohwetse river and ngwaritsi river. some tributaries, notably the klein olifants river (origin near hendrina, joins the olifants river downstream of the middelburg dam), the elands, wilge and the bronkhorstspruit, rise in the highveld grasslands. the shingwedzi river flows close to the northeastern side of the massingir dam reservoir and joins the left bank of the olifants about 12 km downstream from the dam wall.