THE GROWTH OF WATER HYACINTH AND OTHER AQUATIC WEEDS IN RIVERS AND CANALS OF THE SUDAN IS A VERY SERIOUS ENVIRONMENTAL PROBLEM. THE WATER HYACINTH, A SOUTH AMERICAN PLANT, WAS FIRST REPORTED IN THE UPPER NILE REGION IN 1958, AND BY THE MID-1960S HAD INFESTED MUCH OF THE WATERWAYS. CONTROL EFFORTS HAVE NOT BEEN VERY EFFECTIVE, DESPITE SUDANESE EXPENDITURES OF MORE THAN $19 MILLION SINCE 1959. THE WATER HYACINTH INFESTATION HAS SEVERAL NEGATIVE EFFECTS. IT INCREASES WATER LOSS BY AN ESTIMATED SEVEN BILLION CUBIC METERS PER YEAR. IT BLOCKS IRRIGATION-PUMP INLETS AND HYDROELECTRIC POWER PLANTS, CLOGS CANALS, SPOILS WATER SUPPLIES FOR DRINKING, DAMAGES RIVER STEAMBOATS, AND INTERFERES WITH SHALLOW-WATER FISHING. IT CONTRIBUTES TO INCREASED MOSQUITO BREEDING AND SNAIL GROWTH, AND THUS MALARIA AND BILHARZIA. MATS OF WATER HYACINTH HARBOR SNAKES, AND ALSO FORCE CROCODILES TO LEAVE THE RIVER, CAUSING UNREST AMONG THE VILLAGERS. THIS STUDY PRODUCED 16 RECOMMENDATIONS: (1) BECAUSE THE NILE BASIN WATERWAYS OF EGYPT, SUDAN, ETHIOPIA, UGANDA, KENYA, AND ZAIRE ARE INTERCONNECTED, EFFECTIVE CONTROL EFFORTS REQUIRE CLOSE COMMUNICATION BETWEEN CONTROL AGENCIES IN EACH OF THESE COUNTRIES. (2) A BAN MUST BE IMPOSED ON IMPORTING FOREIGN AQUATIC PLANTS TO THE REGION. (3) CURRENT HERBICIDE SPRAYING PROGRAMS NEED TO BE CONTINUED. (4) INSECTS THAT LIVE ON AND DESTROY WATER HYACINTHS NEED TO BE IMPORTED. (5) SMALL BIOGAS GENERATORS FOR PRODUCING METHANE GAS FROM FERMENTED WATER HYACINTH SHOULD BE BUILT AND TESTED. (6) ENGINEERING COMPANIES SHOULD BUILD SIMPLE PRESSES FOR CONVERTING WATER HYACINTH TO ANIMAL FEED. (7) COMPOSTING TRIALS SHOULD BE UNDERTAKEN. (8) GRASS CARP THAT EAT WATER HYACINTH SHOULD BE INTRODUCED. (9) WATER BUFFALO THAT EAT HYACINTH SHOULD BE INTRODUCED. (10) THE POTENTIAL EFFECTIVENESS OF INTRODUCING WHITE CHINESE GEESE SHOULD BE STUDIED. (11) THE USE OF AQUATIC WEEDS THAT CONTROL BILHARZIA SHOULD BE STUDIED. (12) NUTRITION LABS SHOULD INVESTIGATE THE PROCESSING OF WATER HYACINTH FOR HUMAN FOOD. (13) SPIKERUSH PLANTS THAT DISPLACE CANAL WEEDS SHOULD BE INTRODUCED. (14) WATER HYACINTH SHOULD BE USED IN SEWAGE TREATMENT LAGOONS IN EGYPT, BUT NOT IN THE SUDAN. (15) THE RELEVANT SUDANESE GOVERNMENT AGENCIES SHOULD WORK TOGETHER TO ENSURE THAT HERBICIDES USED TO CONTROL WATER HYACINTH AND SNAILS DO NOT ADVERSELY AFFECT THE FISH POPULATIONS. (16) APPROPRIATE RESEARCHERS SHOULD STUDY THE BASIC BIOLOGY, DISTRIBUTION, AND TAXONOMY OF AQUATIC PLANTS THROUGHOUT THE REGION,.