Hapi is the God of the Nile...His name comes from the ancient Egyptian word for the Nile; Hep. He is worshiped not in temples but upon the river itself.
His worship extended through both upper and lower Egypt and in fact all the way to Rome. (The picture below is me with the 'God of the Nile' statue at Capitoline Museum in Rome.)
Hapi was sometimes shown with a Hippo head, or as a buff hunk-God when the Romans were doing the art,
like the statue above from my 2009 Rome trip...but He was usually shown as a man with flabby chest and stomach
(likely referring to his fertility and abundance blessings)
holding papyrus and lotus plants in each hand.
Often He was shown as blue (Likely because the Nile was blue...but many ancient Egyptian and Hindu Gods were shown as blue-skinned.)
The Lotus and Papyrus plants of course gave the people paper, and perfume oil that were both highly prized.
Offerings were made to Hapi by food being thrown into the river. Many prayers were addressed to him, for the yearly flood that made farming the desert lands possible,
and for the blessings the river brought forth, like fish, papyrus, lotus, and other plants, that the Egyptians used in daily life.
Hapi is mentioned in the Pyramid Texts; Utterance 581: "Those who see the Nile when it surges, tremble, the meadows laugh, and the riverbanks are inundated."
Though the yearly floods were destructive the Ancient Egyptians also noted that the floods brought life
to the land by way of water and fertile top soil for the farmers to grow food from in the coming season, so the troubling yearly inundation
was in deed worshiped nonetheless as a blessing by Hapi.
Below are excerpts from the Hymn to the flood- ancient text translated by M. Lichtheim
Hail to you, Hapy, Sprung from earth, Come to nourish Egypt! Of secret ways, A darkness by day, To whom his followers sing! Who floods the fields that Re has made, To nourish all who thirst; Lets drink the waterless desert, His dew descending from the sky. ..... When you overflow, O Hapy, Sacrifice is made for you; Oxen are slaughtered for you, A great oblation is made to you. Fowl is fattened for you, Desert game snared for you, As one repays your bounty. One offers to all the gods Of that which Hapy has provided, Choice incense, oxen, goats, And birds in holocaust. Mighty is Hapy in his cavern His name unknown to those below, For the gods do not reveal it. You people who extol the gods, Respect the awe his son has made, The All-Lord who sustains the shores! Oh joy when you come! Oh joy when you come, O Hapy, Oh joy when you come! You who feed men and herds With your meadow gifts! Oh joy when you come! Oh joy when you come, O Hapy, Oh joy when you come!