A dozen years ago, the list of challenges included keeping the canals, ditches and reservoirs clean so the water would flow effortlessly throughout the lower Rio Grande Valley.
Providing water to about 130 agricultural customers and 19,000 residents served by the Delta Lake Irrigation District of south Texas is no easy task. Among the challenges: an unpredictable water supply, strategic planning so the water arrives when needed and balancing deliveries for everyone in the district.
A dozen years ago, the list of challenges included keeping the canals, ditches and reservoirs clean so the water would flow effortlessly throughout the lower Rio Grande Valley. The arrival of four durable crawler excavators — including a trio of super-long-reach machines — has made that much less of a problem today.
Rio Grande Water
to Farms and Towns
The Delta Lake Irrigation District is the largest of the 26 irrigation districts in the valley. Although it’s called a valley, the area is actually a delta or floodplain that lies along the northern bank of the Rio Grande River that separates Texas from Mexico. The 1,760-mi. (2,832 km) river, which begins in the Rocky Mountains of Colorado, is the fifth longest in North America.
The district, a governmental entity, uses a series of canals, ditches and pipelines to deliver the water needed to irrigate 83,000 acres of agricultural land. Also it provides raw water to five rural communities — Hargill, Monte Alto, Lasara, Lyford and Raymondville — located north of the McAllen and Harlingen metropolitan areas. Before arriving at customers in those municipalities, the water is processed through treatment facilities.
The district’s activities are funded by two sources of revenue: a flat-rate assessment that each landowner pays annually and water sales to farmers and municipalities, either by volume or a flat rate by the acre. Water for agricultural use is diverted 320 days a year because much of the land is double-cropped.
The delta is one of the prime farm areas in the Southwest, producing cotton, sugarcane, sorghum, corn, citrus, vegetables and pasture. There is a big range in farm size — from 10 to 15 acres to several thousand acres. The one thing they have in common is a reliance on water from the irrigation district.
“Planning is key to providing water,” said Troy Allen, general manager of the Delta Lake Irrigation District. “After ordering water from the watermaster’s office [Texas Commission on Environmental Quality], we have to wait three days before we can start our pumps to the farms nearest the originating source at Falcon Dam. It takes another three or four days to reach our farthest customers. We have to push the water a long way.”
During the first quarter of 2015, however, not much irrigation water flowed.
“Since August of 2014, we have had almost one and one-half times our normal amount of rainfall,” Allen said. “We needed the rain really bad, so that’s been a positive. However, maintenance of our ditches and canals has been curtailed and our revenue from water sales is way down.”
When Allen arrived at Delta Lake in 2003, money was tight and maintenance of ditches and canals had been neglected for about six years. Some of the canals had 4 ft. (1.21 m) of silt in them, reducing water flow by two-thirds. The main cleaning tool, a drag line, was broken.
“The first year I was here, we purchased a used super-long-reach [SLR] excavator to clean out the ditches and canals,” Allen said. “We were so far behind that we worked the machine 12 hours a day, five days a week. Within the first five years, we racked up 10,000 hours on the excavator and, as a result, the diverted water routes were in much better shape.”
Do the Job
Once Allen built up the district’s bank account, he was able to purchase more high-performance excavators and a 3.5 cu. yd. (2.67 cu m) wheel loader. He had such good luck with the first used excavator — a Doosan machine — that he returned to the local dealer, H&V Equipment in Progresso, Texas. Due to favorable pricing and financing options, the district presently owns four Doosan crawler excavators.
• DX225LC SLR “super long reach”
• DX300LC SLR
• DX340LC SLR
Each super-long-reach excavator is equipped with a 60-in. (152.4 cm) ditching bucket, while the DX340LC standard arm excavator has a 52-in. (132 cm) trenching bucket. With 165 mi. (265.5 km) of drainage ditches, 42 mi. (67.5 km) of earthen canals and three reservoirs to clean, the Doosan excavators are kept plenty busy.
“The ditches and canals have to be cleaned every three or four years,” Allen said. “Our soil is mostly sandy loam, so it regularly washes into the waterways. Silt builds up, especially after a storm. Before we had the heavy equipment to handle routine maintenance, not only did the silt reach as high as four feet, but we had trees 6 to 10 inches in diameter growing in the ditches.”
The earthen canals are 40- to 120-ft. (12.2. to 36.5 m) wide, and the width of the ditches ranges from 20 to 120 ft. (6 m to 36.5 m). With three super-long-reach excavators and a standard-reach machine, the Delta Lake Irrigation District has the perfect combination of reliable equipment for canal and ditch maintenance.
“Initially, we had to take out trees and brush from several of our waterways,” Allen said. “We used the standard-reach excavator to remove that growth and followed with a super-long-reach machine to work to the center of the canals and ditches. Now, we mostly use the super-long-reach excavators to handle these projects. At times we will have one on each side of the waterway, and when they won’t reach all the way to the middle, we build a pad a little ways out from the bank.”
Allen and his crew have cleaned out so much silt from the drainage ditches that sometimes the banks are built up 6 to 8 ft. (1.82 to 2.44 cm) high, which can reduce the reach of the excavators.
“Our operators do a good job of spreading out the dirt so it’s relatively easy to remove and relocate to areas where banks have to be raised,” said Allen. “We use our Doosan DL250 wheel loader with a three-cu. yd. bucket to load trucks for transport to other locations.”
The district’s trio of reservoirs total about 2,240 surface acres — that’s more than 10 mi. (16 km) of surrounding banks that have to be cleaned of silt every two or three years. That work is handled by the excavators, too. The machines also are used to remove beaver dams, rebuild banks and for new construction.
“A decade ago, there was concern about maintenance of the ditches and canals,” Allen said. “Today we are getting so much more done that we receive compliments all the time. Everything is so much better when you have the right equipment.”