Control of traffic on the inland waterways of the Mekong Delta is one of the key problems facing the Allied forces in South Vietnam. The Viet Cong presently have the freedom of movement required to support logistically all of their combat units in the Delta. Moreover, the present lack of waterways control allows them to use the Delta as a gigantic food supply depot and export foodstuffs and other material to units in other areas of the country. Freedom of movement over the waterways of the Delta also affords Viet Cong units lacking the strength of the better equipped and larger units in the Northern Corps areas, the mobility required to tie down large Government units and to exert their control over areas that would normally be beyond their influence. Viet Cong lines of communication are probably most vulnerable in the Delta.*
Order of Battle Study 66-44, VC Tactical Use of Inland Waterways in South Vietnam, April 28, 1966
In much the same way that US forces in, for example, the Seminole War and the Civil War had used waterways to facilitate military operations, why could we not create special units equipped to utilize the extensive waterways of the Delta to get at the Viet Cong?*
General William Westmoreland
Beginning its life in a torrent of whitewater in the mountains of Tibet, the mighty Mekong River broadens and slows as it cuts through Laos and Cambodia before meandering to a near stop as it empties into the sea in southeastern Vietnam. Sometimes feared for its devastating floods, and on other occasions worshiped for the life-giving fertility of its alluvial soil deposits, the Mekong has long dominated the landscape, culture, and history of Southeast Asia. Nowhere, though, is the Mekong more important to the life of its dependent populace than where its flow slows to a crawl, allowing the river to spread out across the countryside. Fracturing and refracturing as it makes its way across its delta, the Mekong shatters into nine main channels as it nears the sea, giving the river its Vietnamese name of Cuu Long, or Nine Dragons. While nearly one-third of the delta’s 15,500 square miles of wetlands consists of nonarable marsh or forest, including the fabled Plain of Reeds and the forbidding root-entangled depths of the Rung Sat mangrove swamps, the region is also one of the world’s most fertile and productive for growing rice. Villages and hamlets, usually hugging the banks of their parent streams, dot the seemingly endless wet flatness of the delta, sending rice paddies large and small radiating out in all directions. In 1965 the Mekong Delta was home to an estimated 8 million inhabitants, over half of the population of the nation of South Vietnam, boasting a population density of more than 500 people per square mile.
Long ago the Vietnamese, and before them the Khmer, had learned to live in harmony with the twice-daily tidal surge and the yearly flooding of the Mekong to fuel the engine of wet rice agriculture. The ubiquitous paddies, with their countless miles of mud dikes constructed by the hands of untold generations of Vietnamese peasants acting to control and channel the Mekong’s bounty, are often broken by dense tree lines, which produce fruit, help control flooding, and provide shade from the usually oppressive heat. As early as ad 800, the delta population began to add further improvements to the natural drainage system by digging canals. As a result, by 1965 the delta’s 1,500 miles of navigable natural waterways were supplemented by about 2,500 miles of canals. Apart from providing fertility to the land, the Mekong and its tributaries, both natural and man-made, formed the region’s highway network. In vast flotillas of sampans, peasants and merchants plied the area’s waters from the stilted homes of their local hamlets to join in the cacophony of waterborne traffic jams of floating markets in larger villages or cities, such as Can Tho, where farmers gathered from near and far to hawk their goods, buy needed supplies, and socialize. By the time the Americans arrived in Vietnam in great numbers in the 1960s, the delta had only one major hard-surface road – Route 4, which ran from Saigon southward to Ca Mau. While Americans were becoming even further addicted to their cars amid the hubbub of the 1960s, 90 percent of the traffic in the Mekong Delta was by boat.*
Map of Vietnam and Southeast Asia
As the most valuable piece of real estate in South Vietnam, domination over the Mekong Delta was key to the success of both sides in the Vietnam War. For the communist insurgents the Mekong represented the most critical internal source of supplies, especially rice, and the most ready source of replacement troops for the VC. The maze of canals, rivers, and streams in the delta also provided the Viet Cong with a communication network that allowed for dispersal of supplies that had been carried down the fabled Ho Chi Minh Trail to units in the field across South Vietnam. For the United States and South Vietnam, control over the delta offered the best and quickest method by which to throttle the Viet Cong and transform the war from an insurgency to a more traditional conflict. Denying the VC access to the delta’s rice harvest would effectively starve the insurgents and cause their military units to withdraw to Cambodia. Allied supremacy in the delta would also deny the VC local recruits to make good their considerable battlefield losses. Success in the Mekong, then, held for the Allies the hope of altering the very nature of the Vietnam War.
While in some areas of South Vietnam, notably along the Demilitarized Zone, Allied forces squared off against a blend of Viet Cong insurgents and North Vietnamese Army (NVA) regulars, the war in the Mekong Delta was almost exclusively the purview of the Viet Cong. Furthest from the supplies and trained cadre of the North, the communist war in the delta formed the very heart of the insurgency. In 1966 the Viet Cong devoted a high percentage of its strength, an estimated 82,545 men, to military efforts in the delta. Of these, 19,270 were combat troops, 1,290 were support troops, 50,765 were part-time guerrillas, and 11,220 were members of the political cadre. Viet Cong penetration of the delta was often quite deep, with control over some villages and areas dating back to the early stages of the Viet Minh’s war against the French. In some cases the VC presence was quite open, with major base areas in the Plain of Reeds, the U Minh Forest, and the Cam Son Secret Zone functioning as military supply depots and training sites of long standing. Often, though, VC control was covert, allowing the local apparatus of the South Vietnamese state to function while a VC shadow government levied taxes, gathered supplies, and recruited behind the scenes.
Born from the wreckage of French colonialism after Dien Bien Phu, South Vietnam had lurched from crisis to crisis, which had never allowed government institutions to penetrate the delta completely. By the early 1960s, though, the leadership in Saigon had worked hard to install its rule in the region, in part through the implementation of rural security schemes including the Strategic Hamlet Program. By 1962 much had been accomplished and the war in the delta stood at a point of stasis. However, 1963 proved to be a turning point, especially in the view of South Vietnam’s American sponsors. Politically, the overthrow and assassination of South Vietnamese president Ngo Dinh Diem resulted in a period of chaos and governmental instability that had a serious impact on the fighting ability of the Army of the Republic of Vietnam (ARVN). Militarily, the outcome of two major battles in the delta caused the US to question South Vietnam’s ability to survive. In January 1963 an ARVN force that enjoyed a 5:1 superiority in manpower cornered a VC unit of 300 near the village of Ap Bac. The VC, though, had fought well, downing five helicopters in the process, and survived to withdraw during the night. In December 1964 the Viet Cong 9th Division seized the village of Binh Gia. Reacting predictably to the affront, ARVN forces rushed to the scene only to be ambushed and virtually destroyed.
Judging that South Vietnam stood on the verge of defeat, the US sent its first combat forces ashore on the beaches outside Da Nang in March 1965. Initially US infantry units supported the bombing of North Vietnam, Operation Rolling Thunder, by guarding sensitive air bases and installations. By late 1965, though, the US mission had broadened considerably, allowing for offensive operations to find, fix, and finish the communists by locating and destroying their major troop concentrations. In considering profitable avenues of attack, the planners at Military Assistance Command, Vietnam (MACV) quickly turned their attention to the delta. Facing the Viet Cong in the region was an average of 40,000 ARVN forces, with the 7th Division at My Tho, the 9th Division at Sa Dec, and the 21st Division at Bac Lieu. Augmenting the regulars were units from the Regional Forces and the Popular Forces, undermanned and often poorly supplied local units tasked with protecting villages and districts. The success of the South Vietnamese government forces in the delta varied widely. While some areas (especially those containing Catholic villages) were considered “pacified,” others were under nearly complete VC rule, with government forces in An Xuyen Province only controlling 4 percent of the countryside. In total the Viet Cong enjoyed open control of 24.6 percent of the delta, enough to choke off the critical flow of rice to the markets of Saigon. In 1963 rice arriving in Saigon had reached a high of about 4.5 million tons, but by 1966 that total had dropped to 3.3 million tons, making it necessary to rely on imports.
Although MACV did not believe that ARVN forces in the delta were on the verge of defeat, the resurgence of the Viet Cong in the area in July 1965 prompted Brigadier General William DePuy – MACV assistant chief of staff for military operations – to direct a study on basing US troops in the delta. A unique difficulty, though, quickly came to light. Given the waterlogged nature of the terrain, coupled with its dense population, there was no uninhabited land area available large enough to house a sizeable US troop population. In addition, although the vast, flat expanses of the delta were conducive to helicopter operations, the lack of roads would make supplying and maneuvering a concentration of US forces nearly impossible. While the planning staff developed the innovative idea of creating a base by dredging silt from the bottom of the Mekong to form new land where none had existed, others focused on the past to find a solution for the riddle of operating in the delta.
The French, in operations later continued by the South Vietnamese, had utilized troops and firepower based aboard flotillas of modified World War II-era landing craft to combat the Viet Minh along the river networks of Vietnam. The flotillas, known as Dinassauts, had achieved considerable success both in supplying distant outposts and in providing tactical mobility. MACV planners took the concept one step further, contending that massive LSTs (landing ship, tank) could be converted into floating barracks, which, when grouped together, could form a mobile floating base from which entire American brigades could operate. The Mobile Afloat Force, as the idea was originally known, had the advantage that it could shift its location across the delta to hound the Viet Cong troops no matter where they fled. When briefed on the idea, Rear Admiral Norvell Ward agreed that the rather outlandish concept had merit.
In early December 1965, DePuy impressed Westmoreland with a briefing on his plans, which came to include both the construction of a land base and the formation of the Mobile Afloat Force. After assent to the scheme by Westmoreland’s superiors at Headquarters, Pacific Command, the Joint Chiefs of Staff in Washington, D.C. tentatively approved an additional infantry division for use in the delta, initially designated “Z Division.” The planning finally culminated on March 15 with a MACV study, “Mekong Delta Mobile Afloat Force Concept and Requirements,” which laid out the detailed blueprint, ranging from logistic support to proposed dredging operations, for basing US infantry in the delta.
During final planning for the Mobile Afloat Force plan in Saigon, the Joint Chiefs gave the go ahead to reactivate the 9th Infantry Division at Fort Riley, Kansas, to serve as “Z Division” in the Mekong Delta. The choice to reactivate the 9th Division was no accident. Westmoreland himself had seen extensive service with the 9th in World War II, commanding the 60th Infantry and serving as chief of staff of the division in both France and Germany. The strategic decision arrived at in the halls of power in Washington had the effect of tossing a rock into the American national pond, causing ripples that reached into living rooms and dining rooms across the nation that changed many young lives forever.
* PLAF Tactics in Using Canals, Waterways, 1965. Headquarters US Military Assistance Command, Vietnam. Office of Assistant Chief of Staff – J-2. Order of Battle Study 66-44, VC Tactical Use of Inland Waterways in South Vietnam, April 28, 1966. Douglas
* General William Westmoreland, A Soldier Reports (New York: Doubleday, 1976), p.208.
* Much of the information on the nature of the military operations in the Mekong Delta comes from Major General William B. Fulton, Vietnam Studies: Riverine Operations, 1966–1969 (Washington, D.C.: Department of the Army, 1985), pp.17–30.