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**Objectives** media type="custom" key="15542880" align="right"This paper is a collaborative effort by civil engineering and water resource disciplines to capture past, current, and future states of the Rio Puerco watershed and stressors that shaped these conditions. We will 1) introduce the physical and social features in the catchment, 2) explain historical developments that have shaped the Basin, 3) address impacts, 4) identify restoration activities, and 5) identify potential strategies for restoration efforts in the Puerco watershed. Overall, we hope to provide a deeper understanding of restoration principles and practices as they pertain to the Rio Puerco.

**INTRODUCTION - AN OVERVIEW** =Physical Description = The Rio Puerco catchment area is 2,119 square miles in New Mexico, United States. It flows through three counties; the Rio Puerco headwaters are in Sandoval County and flows south through Bernalillo and Valencia Counties (Hebard and Johnson, 2004). The muddy stream flows of the Rio Puerco shaped its characteristic name, "pig river" or "dirty river" in Spanish. The Puerco is an important tributary to the Middle Rio Grande because it transports the highest average annual sediment concentrations due to extremely high erosion rates. Total sediment production in the Rio Puerco supplies approximately 78% of the sediment entering Elephant Butte Reservoir (Aby et al. 2004). Flow in the Puerco is ephemeral over a majority of the river, and only occurs in response to precipitation events (Coleman et al. 2006). Overall, the Rio Puerco delivers a small percentage (4%) of annual flow to the Rio Grande (Watts et al. 2006).

Geology
The Rio Puerco watershed geologic units are primarily composed of siltstones and shales (Watt et al. 2006). These geologic units are relatively erosive during rainfall events and act as sources of suspended sediment causing turbidity levels to be extremely high in the river, averaging 79,000 mg/L (Bureau of Reclamation 1993). In response to sediments transported downstream, the Rio Puerco Basin displays valley filling. Another key characteristic of the Puerco catchment is high topographic relief that contributes to an increase in erosion from an increase in stream power as water is transported down slope. Most of the catchment area is considered to yield high sediment from erodible soil characteristics.

**Climate** Summer monsoonal rainfall supplies most of the basins precipitation with annual ranges of 12-20 inches. Headwater reaches are additionally supplied with snowmelt runoff in early spring. Two distinct hydrographs represent the Puerco catchment; headwater reaches have peak stream discharge in spring (May) and the lower basin peak discharge is in late summer supplied by monsoonal rainfall. Summer monsoonal precipitation events are known to be scattered with high intensity rainfall that can generate flashy runoff and impact erosion of landscape. Convective storms events dominate in the lower basin reach (Gellis 2006). 

**Erosional Rates** Infiltration rates vary spatially (Rio Puerco report) due to topography, vegetation, and geology. Due to low infiltration rates runoff serves to transport sediments into tributaries and along the main stem. Figure 1 shows the catchment contributes substantially to the sediment load. Tributary arroyos influence sediment loads in the main stem in a disproportionate manner. In particular, the Arroyo Chico tributary is an important hydrologic and geologic contributor to the Puerco serving as a major source of water and suspended sediments, 52% and 34% respectively (Rio Puerco report). Record sediment concentrations of 400,000 ppm have been observed at the confluence (Gellis 2006). Sources of sediment are derived from erodiable 1) main stem channel, 2) tributary channels, and 3) gully, sheet, rill (Happ 1948). Erosion (incision) and aggregation (filling) rates are driven by climate forces such as precipitation and temperature. Cyclical periods of degradation/aggregation are attributed to temporal variability in climate patterns that drive biological and physical controls of infiltration and runoff of precipitation. When stream discharge increases in response to climate forcing, stream power increase and so does the capacity for sediment transport.

**Socio-Economic** Population dynamics and established archaeological sites range within the basin (Rio Puerco report). Allocation of land ownership ranges from tribal, private, state, to federal. Major land owners are BLM (39.5%) and private (30.23%). Types of land use vary with land ownership but typically include ranching, logging, recreation, residential and commercial uses. Land-management practices are poorly implemented on government and reservation lands; therefore, the recovery of the system from restoration activities like planting of vegetation may be underestimated.

**Collaborative Efforts** Improvement of the Puerco catchment needs involvement from researchers, local organizations, and state and federal agencies. The Rio Puerco Management Committee (RPMC) involves the collaboration of multiple stakeholders with diverse cultural and political backgrounds that express similar interests in restoring the Rio Puerco catchment and “has focused on strengthening community resolve and capacity to reduce sediment, control erosion, and promote healthy vegetative communities” ([]). The importance of continued monitoring of restoration structures was assessed by Phippen and Wohl (2003) in the Rio Puerco and found poor functionality of structures due to improper installation and continued maintenance. Thus, the role of RPMC in restoring the Rio Puerco is imperative for successful restoration goals and demonstrates the need for involvement of local communities. Additional subcommittees at the regional level involved in watershed planning include the Interstate Stream Commission, Middle Rio Grande Council of Governments and Cuba Soil and Water Conservation District. Their focus is on water and land usage within the Rio Puerco catchment.

=<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Ecological Characteristics = <span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">Extensive ecohydrologic research has been done on the Rio Puerco Basin due to high sediment loads and degraded ecosystem structure and function. Riparian vegetation is an important biological component that influences the load of suspended sediments and channel activity through infiltration and soil stability. Geomorphology and vegetative cover vary longitudinally between headwater and downstream reaches and influence erosional rates in the Rio Puerco catchment. The combination of sparse vegetation and small sediment sizes in the valley contribute to erodible banks and floodplains in the Puerco Basin (Watts et al. 2006). Suspended sediment load (SSL) is positively related to stream flow and inversely related to vegetative cover, such that higher annual peak flows results in higher SSL and lower density of vegetation along the riparian zone (Love 1997).

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Vegetation cover consists of sparsely covered grasses like snakeweed and wheatgrass, and shrubs (USGS). Invasive species like juniper and salt cedar are well documented in New Mexico and have displaced native vegetation. An attempt in 2003 to eradicate salt cedar at selected reaches along the Puerco using herbicides resulted in an increase of bank erosion from loss of bank stability provided by invasive vegetation (Vincent et al. 2009). This study shows that removal of nonnatives can have unintended consequences of reduced bank stability and increase transport of suspended sediments. Restoration activities in the Puerco are complex due to interconnection of vegetation and erosion and need to account for these relationships.

<span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">**HISTORY OF DEVELOPMENT/LAND USE PATTERNS OVER THE PAST 100+ YEARS**

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<span style="color: #000000; display: block; font-family: arial,helvetica,sans-serif; font-size: 16px; text-align: left;">**Historical Physical Attributes** <span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">The earliest historical description of the Rio Puerco was captured by Juan de Onate in late October of 1599. As Onate crossed the River near Cabezon Peak, he described the water as deep and that there were many cottonwoods lining the rivers banks. He also depicted the landscape as “lush, rich, and fertile”. It was recorded that there were so many cottonwood trees along the river that a legal dispute arose as to who owned the rights to the timber. In 1692 Diego de Vargas first crossed the Rio Puerco just west of what is now Albuquerque and observed that the river was completely dry. Later upon returning he recorded that the water was “so deep that the soldiers had to carry provisions and equipment on their shoulders.” He described the river as fast flowing and muddy. Today the cottonwood tree population has disappeared almost entirely along most reaches of the river.

<span style="color: #000000; display: block; font-family: arial,helvetica,sans-serif; font-size: 16px; text-align: left;">Early surveyors of the Rio Puerco noted that the river was strictly ephemeral after the first ten miles of its existence. Rains quickly turned the river into a muddy flood. Gage data recorded at the Santa Fe Railroad crossing showed that the annual discharge ranged from 3,280 to 229,000 acre-feet from 1913-1925. The greatest flood recorded was 14,000 second-feet (equivalent to 14,000 cubic feet per second) (Bryan 1928), however, it is expected that floods twice this magnitude were likely to have occurred. American geomorphologist Kirk Bryan (Bryan 1928) mentioned that in 1928 the channel had an average depth of 28 feet and a width of 285 feet and the valley varied in its width from a quarter of a mile to three miles. He mentions that a terrace was located above the stream grade and that this abandoned flood plain could no longer be over banked by even the largest of floods. He noticed that a new cycle of erosion was already in process for the river and called it a small gully. Bryan dated arroyo cutting throughout the Southwest by examining early travelers’ accounts and talking with old-time ranchers, and he was able to document a post-1880 initiation of severe erosion in most areas. In his article his interviews of the oldest residents on the Rio Puerco repeat time and again that the channel had been deepening and widening throughout their lifetimes. In the late 1880’s residents noted that rapid deepening of the river had begun. There are conflicting accounts of the rivers physical attributes at this time. Some say that the river had no banks or inconsiderable ones at least. With no bank sides floods spread over the entire valley floor, but travelers observed that at much earlier dates considerable high banks existed in certain locations. Bryan used field notes from early public land surveys beginning in 1855 to try to get an accurate picture of what the Rio Puerco truly looked like. He noted that the early surveyors did not comment on the height of the banks but have rather extensive recordings of the distance between them. Bryan assumed that the banks were so low and unimpressive to the surveyors that they didn’t find them worth mentioning. <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">In 1849 Simpson (Bryan 1928) crossed the river approximately 5 miles above Cabezon. He recorded that the channel was 100 feet wide containing stagnant pools of water. The banks at that time were 20 and 30 feet high and had to be cut down to allow the passage of artillery. In the 1877 survey of the M. and S. Montoya Land Grant, just five miles upstream of the town of Cabezon, Watts and Pradt (Bryan 1928) recorded that a new channel with high banks showed evidence of recent cave-ins and falling trees. They also stated that this new channel was located west of the old channel that happened to form the eastern boundary of the grant which was evidence that the river had found a new path. When it was resurveyed in 1899, Pradt noticed new changes to the river. He surveyed the new channels width as 198 feet. In 1906 J.H. Walker noted that the new channel was still in the same location but was now 224.4 feet wide and 20 feet deep.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Former residents of Cabezon describe the channel characteristics around 1870 and recall that the flood plain of the Rio Puerco did not have a deep channel. The river was discontinuous for most of its length. There were large cottonwood tree groves and high grass and weeds. The river was shallow and settlers could divert water by felling a cottonwood tree across the stream creating a dam. Once the river would flood the water would wash around it and the channel would become enlarged due to incision into the bankside. Small bridges built over the river would become useless after large floods because the river would overbank and change position. Between 1885 and 1890 the channel began experiencing river cut down and wells in the town went dry and had to be abandoned. Residents of Cabezon were forced to haul water from a small reservoir 3 miles west. By 1900 residents began moving away from Cabezon and since 1910 overbanking at Cabezon has become impossible.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Cabezon was not unique in the rivers channel cutting experience. Settled locations above and below Cabezon were also noticing drastic changes in the river. Survey data for these areas is not quite clear but resident recollections show that the channel was in fact widening and deepening. The earliest records show that in places on the Rio Puerco the banks were as high as 20 to 30 feet and at other sites the banks were so low that they were not recorded. Farmers took advantage of the water that flooded the valley floor by raising crops of beans, corn, and wheat. Before the late 1880s the channel, being ephemeral, was prone to numerous floods of short duration. Often floods of large magnitude would overbank and inundate the floodplain. Historically, the Rio Puerco was not continuously connected but was rather a series of discontinuous trenches. When flood waters would overbank the existing channel, the river would “hop” to a new trench and create a new channel to follow. It was not until after 1880 that the Rio Puerco began incising and forming a permanent path. This new deep channel was formed from the mouth headward and reached Cabezon 110 miles away somewhere between 1885 and 1892. From the records of abandoned towns above Cabezon, it is safe to assume that the cutting of the Rio Puerco began in the late eighteen eighties and is still in progress today. At the time that Bryan published his report in May 1928, 42 years of records showed that the amount of mud and silt moved out of the Rio Puerco into the Rio Grande was estimated to be 394,882 acre-feet (an average rate of 9,400 acre-feet per year).

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Channel Cutting, Incisions, and Arroyos** <span style="font-family: arial,helvetica,sans-serif; font-size: 16px;"> <span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">There are two unmistakable draws of attention to the Rio Puerco. The first is that it undeniably carries a huge amount of sediment that is undesirable. Second, the river that once was described as wide and shallow has been widening and deepening for over a century. This of course alludes to the first issue of sediment transport. The phenomenon known as 'arroyo cycling' is typical in ephemeral streams. Ephemeral streams are normally dry for long periods but channel storm water during precipitation events. Flashy storms can cause cutting (incision) which is the movement of large volumes of sediment. The next step in the cycle is aggradation, where the arroyo once again fills with sediment. This is the exact scenario experienced in the Rio Puerco. The cycle of incision and aggradation is the reason for the drastic changes to the geomorphology of the river.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The material that is added within the channel comes from two different sources. One is the collapsing of channel walls. This occurs when the soil materials are weakened after a storm event by becoming saturated. The shales and sandy material found in the soils of the Rio Puerco are easily eroded and deformed once in contact with storm waters. The second is a process called piping. Piping happens when water from precipitation flows into the arroyo wall soils. The water finds a pathway in the soft material and can carve out cave-like voids in the sides of the arroyo wall. These ‘caves’ can reach fairly deep into the arroyo wall and are large enough to fit large automobiles.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Overgrazing** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The decrease in vegetation along the Rio Puerco has been blamed as one of the factors causing the channels’ arroyoing cycle. Livestock was introduced into the Southwest in 1540 by the Spanish. Settlement of the Spanish in the New Mexico area began with Onate’s conquest in 1592. The settlements were constantly harassed by the Navajos and they were ordered to move into the Rio Grande Valley in 1823. The size of livestock herds was not well documented although there are reports that just north of Cabezon on the Rio Puerco it is claimed that there was a herd of 10,000 cattle. The Navajos also had acquired livestock and horses and this added to the amount of herbivory of foliage along the river. Destructive erosion from livestock became evident during the period of 1885 to 1890.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Although it seems coincidental that overgrazing and arroyo-cutting began at the same time it is only one hypothesized reason. At the time, the climate may have allowed just the right amount of vegetation to grow along the river to discourage erosion. It may or may not have been enough to overcome overgrazing. There is some evidence of an ancient arroyo on the Rio Puerco that has gone through the arroyo cycle. This cycle is one of alternating processes as it changes from sedimentation to erosion and back to sedimentation in the absence of grazing stress.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Causes of Accelerated Arroyoing** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">As previously mentioned, the Rio Puerco experienced accelerated erosion along the channel in the 1880s. Initially this arroyo cutting was assumed to be the cause of two specific sources; the decline of protective vegetation due to decreased rainfall, and by the overgrazing of excessive numbers of livestock. It was estimated that nearly four million sheep grazed the lands of New Mexico by the year 1880.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">More recent studies of the Rio Puerco now indicate that climate may be the greatest cause of the erosion. Two models that have received attention relating to arroyo cutting in the Southwest are the Bryan-Antev and Martin-Schoenwetter models. The former relates arroyo cutting to drought and a poor vegetation cover while the arroyo filling is due to higher rainfall and improved vegetation cover. The latter associates gullying with increased summer high-intensity rainfall, when there may actually be a greater annual rainfall and an increased vegetation cover. Based on field work and historical studies on the Rio Puerco, Tuan was able to provide evidence that supports the Martin-Schoenwetter model (Denevan 1967) and notes the relationship is not as strong between modern arroyo cutting and overgrazing as had been previously thought. The increase in high intensity rainfall is more likely the reason for the arroyo cutting problem on the river.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">There is evidence that some areas of New Mexico had experienced gullying long before the increase in the sheep population before the 1870s. Observation of more modern gullies have occurred with very little or no grazing from sheep or cattle. It should also be noted that Simpson, as suggested in an earlier section of this paper, noted that the Rio Puerco in 1849 had channel walls that were between twenty to thirty feet high. This may serve as proof that the Rio Puerco has been undergoing an arroyo cutting cycle much earlier than the 1880s. Simpson notes that the river through much of the Rio Puerco Valley was a series of discontinuous trenches. The river did not become continuous until after 1880 as the river cut deeper into the earth and finding a permanent path.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Gages** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">During the period of 1948-1956 there were five USGS data stations operating along the main stem of the Rio Puerco and two of its major tributaries: the Rio San Jose and the Arroyo Chico. The data collected at these stations were for suspended sediment and daily suspended sediment discharge. Currently there are only two stations operating in the basin. They are located on the Rio Puerco at Bernardo and just above the Rio Puerco on the Arroyo Chico. The average annual suspended-sediment load recorded between the years 1948 to 1996 at the Rio Puerco near Bernardo was 4.44 million tons, which is 4.03 metric tons (Gellis 2006).

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">During the period that all five of the stations were collecting data, thirty to fifty percent of all runoff and transport of suspended-sediment load occurred in August and/or September. Rainfall events occurred during the July to September monsoonal season. The gage at Arroyo Chico showed peak runoff in May from snowmelt in the Nacimiento Mountains just above Cuba.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The largest upstream contributor of suspended sediment recorded from 1949 to 1955 was the Arroyo Chico. The Arroyo Chico drained twenty-four percent of the basin, delivered thirty-four percent of the suspended-sediment loads, and contributed fifty-two percent of the runoff. The Arroyo Chico was recorded to deliver the highest average annual sediment amount of any station at 2,721 tons per square mile. It also had the highest total sediment concentration of 190 tons of sediment per acre-feet of runoff. The gage at the Rio San Jose at Correo recorded the lowest amount of sediment transport of the five stations. The difference in sediment transport at the two locations is an indication of differences in soil types, hydraulics and geology.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Trends In Suspended Sediment** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Gellis reported that suspended sediment loads and average annual suspended sediment concentrations in the Rio Puerco decreased in the recorded years from 1948 to 1996. These gages were at the locations on the Rio Puerco near Bernardo, Rio Puerco above the Arroyo Chico, and the Arroyo Chico near Guadalupe. Gellis attributes this decrease to arroyo evolution. The arroyo evolution model is a process of systematic changes in the geometry of the channel, the process follows:

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Channel entrenchment, from channel deepening to channel widening;
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Channel widening leads to less erosive flows;
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Then increased areas on the floodplain for colonization of vegetation and channel aggradation;
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The increase in sediment deposition over time leads to a decrease in suspended sediment loads.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Love (1997) stated that the arroyo evolution model is based largely on a headward erosion model. Love also concluded that using the erosion model may not be applicable in the main stem of the Rio Puerco.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Through data collection, Elliott (1979) found that:
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The upper reaches of the river had:
 * Large width-to-depth ratios
 * Contained considerably small amounts of silt and clay sized material within the channel perimeter
 * Decreased amounts of vegetation along the river
 * A lateral shifting channel that was actively eroding
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The downstream reaches had:
 * Small width-to-depth ratios
 * Large amounts of silt and clay sized material in the channel perimeter
 * High amounts of vegetation
 * A relatively stable channel position
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Upstream reaches in 1977 were similar to lower reaches on the river in the 1930s:
 * Elliott assumed that channel stabilization was progressing from downstream to upstream reaches
 * After resurveying the 1977 cross section in the years 1994 and 1997, Elliott found that this assumption was correct

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">There are many hypothesized reasons for the reduction in the suspended-sediment loads in the Rio Puerco. One of these reasons may be credited to land management treatments that intend to reduce erosion effects on the river. Agencies including the Bureau of Land Management, National Resource Conservation Service and others have recognized the need for erosion control on the river since the 1930s. These agencies have implemented erosion reduction methods and have worked towards improving the vegetation cover along the rivers banks.

=<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">IMPACTS = <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The last section of this wikispace focused on the major changes to the basin in the basin 100 years. The historic section included numerous examples of changes within the Rio Puerco that altered the mechanics of the river. The impacts section will explore how multiple disciplines explain why the flood peaks have drop off drastically in the 1970’s. The actual causality has not been determined. Some of the explanations include a change in watershed management practices, irrigation within the basin, construction of dams, changes in vegetative cover, changes in sediment loads, and human impacts from development and construction within the basin.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Dams** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Dams impact the temporal variation of water distribution in a watershed. According to Bureau of Land Management (BLM) records dams where introduced into the Rio Puerco basin beginning in the 1930’s. Currently, there are at least 647 dams located in the basin which are comprised of 247 retention dams, 119 detention dams, and 281 diversion dams and dikes (BLM 1993). More recently, a survey was conducted on 191 dams that were constructed from 1949-1971 and found 51% of the dams were dysfunctional without corrective maintenance, 35% were totally breached, and 14% of them were in fair condition and those required routine maintenance (Kuka 1999).

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Human Activity** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Human settlement can rapidly alter ecosystem structure and function. During the mid-1960s, New Mexico Department of Transportation (NMDOT) constructed New Mexico highway 44. (Coleman et. al. 2006). To minimize construction costs, NMDOT removed a portion of a naturally sinuous channel, by channelizing a 1.1-mile reach of the Río Puerco upstream from La Ventana. The channelization of the Rio Puerco occurred between 1965 and 1966. Other human activities such as fire and cattle grazing, could have contributed to vegetation alteration and removal (French et al. 2009). Evidence of human fires include very fine to fine charcoal fragments that have been documented in every soil/sediment type along the banks but tend to be predominate in the sands and silts areas. Documented programs started as early as the 1930’s could have hindered the natural ecosystem cycles. Vegetation thinning programs such as controlled burns were used to promote grass growth. The controlled burns might have accelerated the amount of sediment and erosion in the river (BLM archival record 1930-1999). As previously mentioned, the Rio Puerco has always been considered a sediment laden river and there was a desire to decrease the sediment as early as the 1930’s. Documented programs indicate that attempts were made to decrease the sediment loads (Phippen & Wohl 2003). It is unclear if any of the programs that were implemented during this time were successful in decreasing the sediment loads during peak flood flow conditions.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Vegetation** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">A change in vegetative cover is another explanation for the decrease in river flow. Tamarisk, common name salt cedar, was introduced to the Rio Puerco Basin in 1926. Salt cedar was used to provide bank-stabilization and act as a natural erosion control structure (Aby 2004). A decrease in water flow could be attributed to the tamarisk acting as a sponge and withdrawing water from the river. In addition to tamarisk in the valley, the Rio Puerco was used by ranchers as grazing land for cattle. Physical indications, such as overgrazing, could have directly led to decrease in vegetative cover (Bryan 1925; Scholl & Aldon 1988; Phippen & Wohl 2003). Cattle prefer to graze in riparian areas but cause damage such as vegetative destruction and compaction of stream banks (Platts and Nelson 1985; Trimble and Mendel 1995). The destroyed vegetation and compacted stream banks from the overgrazing can cause an increase in runoff. An increase in runoff creates a scenario providing more erosive power to a stream. With more power, degradation of the banks and riparian area can change rapidly. Cattle make the situation worse by moving across the basin, grazing and compacting the soil. The cattle reduce the soil infiltration and increase surface runoff and sediment removal (Scholl 1989; Castillo et al. 1997).

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Sediment in the Rivermedia type="custom" key="15672014" align="right"** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The amount of sediment in a river is a major driver in river health. Two theories exist for causing a decrease in flow; a decrease in sediment loads or an increase sediment load. A discussion of both cases is included below.To better understand sediments loads, a Google map showing NRCS soils maps has been included as a reference.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Where’s the Sediment?** <span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">A decrease in suspended-sediment loads at the Rio Puerco has caused a decrease in annual peak flows since the 1930’s (Love 1997). An increase in vegetation led to an increase in roughness, slowing the river down and increasing the sediment deposition. This increased vegetation could be responsible for decreasing the amount of suspended-sediment loads (Love 1997). The National Resource Conservation Service, Bureau of Land Management,, Bureau of Indian Affairs, and other governmental agencies implemented programs that reduce erosion by improving vegetation cover. These improvements date back to the 1930’s (Burkham, 1966; Soil Conservation Service 1977). Some of these programs include the planting of tamarisk to decrease erosion and improve the riparian area. With numerous dams and water retention structures, a more regulated flow is common. A temporal variation of water decreases the chances of flooding. Smaller peaks on a hydrograph make it difficult to provide the shear stress needed to add particles into the river. Smaller particles, such as silt and clay, are more difficult to dislodge because of cohesive forces (Thorne and Tovey 1981; Papanicolao 2007).

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Why So Much Sediment?** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">An overtaxing or burden of sediment may explain for a decrease in the river peak flows. Relative to other rivers, the Rio Puerco is has a particularly high sediment load. The soil type and intensity of precipitation could reach the maximum effective discharge and produce the maximum sediment in the river. For an explanation of flow vs. sediment loads, see the major topic @hydrology then subsection discharge settlements. A higher composition of shales and siltstone in the basin erode easily and increase sediment loads. The Rio Puerco basin headwaters include high terrain with steep slopes providing sediment-moving power that result in higher runoff because of the substantial topographic relief. Steeper slopes and more sediment-moving power make it difficult for solids to settle. The Rio Puerco river bed consists primarily of silt, sand, and clay. Other rivers with larger particles, such as gravels and cobbles, are more difficult to dislodge because of their greater mass. Due to the lower quantities of larger particles in the river, the Rio Puerco is susceptible to higher sediment loads. The Rio Puerco has high erosion potential due to unregulated flows, and sandy banks with low critical shear stress causing sediment, therefore chocking downstream flows and causing pools of water.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Weather- Climate Change** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">A changing climate has made major headlines in the news. A shift in the type and frequency of storms could be a major driver in the flow. For example, weather patterns could decrease the frequency of rain, but create a greater frequency and intensity of thunderstorm events (Cooke & Reeves 1976). Increase in temperatures can impact flows and vegetation along the river (Antevs 1952). Warmer temperature increases the amount of moisture the air can hold. Since the air can hold more water, an increase in the precipitation intensity would increase the runoff, also creating more stream power and causing more erosion. This erosion will cause copious degradation and aggregation along the channel. The higher temperatures make it harder on vegetation which reduces the amount of vegetation cover. Higher sediment loads steepen valley sides and create higher discharge through valley floors, accelerating the degradation of the channel (Cooke & Reeves 1976).

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Watershed Management** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Human decisions, including management practices of the land, could be blamed for the dynamic changes in flows. The Rio Puerco flow has consistently declined since the late 1940’s (Gellis 1991). Rules and regulation set by the BLM toward grazing practices within the basin could have impacted water and sediment loads. Tamarisk was added for bank stabilization without understanding the amount of water consumption required to keep the plants’ health. The headwaters of the Rio Puerco contain dense forests of spruce and mixed conifer trees. Forest management practices have allowed for forest overgrowth. With more trees within the basin, larger percentages of water are lost due to evapotranspiration. The spruce and mixed conifer intercept more water therefore decreasing the amount of runoff that makes it into the Rio Puerco (Middle Rio Grande Water Plan).

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Irrigation** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">One explanation for a low population and agriculture within the basin could be explained by a “no flow” or “no flow for extended periods” along a large portion of the reach (Shoemaker 2000). Based on a 2000 NMOSE report, over 89% of the water withdrawals are from agriculture using 2040 acres-feet. (Wilson 2003) Shoemaker, in a 1987, reported over 3200 acres –feet were used for irrigated. To understand the size of agriculture demand, over 3100 acre-feet was for riparian usage as reported by Wilson (2003).

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Interactive Rio Puerco Map** <span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">It was unclear the actual driver that has caused a decrease in the peak flows. To help explore the reason for the decrease, an interactive map was created, using Google Maps API. The map includes stream gages, stream flow, watershed boundary and Geo-referenced photos of the landscape. The photos show the varied terrain along with the diverse land cover and soil types within the basin. Due to the restriction of a wikispace, the Google Map could not be embedded into this page. External link: The Rio Puerco Interactive Map

<span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">On the right (figure 6) is a screen shot of The Rio Puerco Interactive Map. The image on the right is not interactive and only a screen shot. To enter into the interactive map please select the link above. Blue lines indicate stream flow and flags are the locations of stream gages. The red outline is the boundary of the watershed and the balloons are the Geo-referenced photos. All of the features contain attributes, to view a attributes, just click on a icon and a photo or list of attributes will appear.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**RESTORATION ACTIVITIES** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">[|Rio Puerco Management Committee] (RPMC) a collaborating group that meets regularly and undertakes restoration projects within the Rio Puerco watershed. It consists of a partnership between 9 federal agencies, 5 tribes, 13 state agencies, 6 non-profits, interest groups, residents, landowners and interested citizens. <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The Rio Puerco Management Committee has stated that its restoration goals for the Rio Puerco are: <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The groups’ focus is on reducing sediment, controlling erosion, and promoting healthy vegetative communities. It is a community-based monitoring approach which also gathers data to show effectiveness of their project. In 2003, the RPMC received an EPA Watershed Initiative grant because of their low-tech erosion control methods which uses available materials and successfully demonstrating landowner projects, workshops and summer youth projects. Their goals are to improve water quality, increase the quantity of water and agricultural yield, and “reduce overall impairment of the watershed.” So its projects will include:
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">It was established by the Omnibus Parks and Land Management Act of 1996.
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The [|Rio Puerco Alliance] (RPA) is the non-profit arm formed by members of RPMC.
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">sediment reduction,
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">vegetation and habitat improvement and
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">to support other watershed factors such as inter-agency cooperation, protecting cultural resources and public awareness and education.
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">In-channel stream restoration Using available materials like rocks and logs to prevent further erosion and to harvest water.Using available materials like rocks and logs to prevent further erosion and to harvest water.
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Induced meandering which adds stream sinuosity. It will move more slowly with less erosive power. This gives opportunity for vegetation to grow which lends to bank stabilization.
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Water harvesting and erosion control
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Monitoring Working with schools, youth projects and through public presentations. Concepts on grazing management, monitoring techniques, roads management, and erosion control are presented at public events, festivals, water fairs, local newspapers, distribution of field guides, and public "listening sessions"
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Using photo documentation, conducting stream surveys, water quality monitoring and riparian and upland monitoring.
 * <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Education

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Completed Restoration**

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">There were five objectives to restoration stated in the Project Summary Report on the Rio Puerco: Engineering, Environmental and Geomorphology Evaluation:
 * 1) <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Regulatory environmental oversite and assistance to the Highway Department during Highway 44/550 highway and bridge planning.
 * 2) <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Environmental Assessment (EA)/Impact Statement for the La Ventana project as required by the National Environmental Policy Act (NEPA) for public lands
 * 3) <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Habitat enhancement to riparian and wildlife habitat is seen as a long-term benefit to the site.
 * 4) <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Water quality improvements through erosion control and stream design implementations.
 * 5) <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Educational, environmental awareness and technical transfer benefits in an effort to support local watershed associations and bringing up new cooperative relationships.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">SAN PABLO - July 2002 to fall of 2005: <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">This three year project was funded by a 319 grant from the New Mexico Environment Department and supplemented by additional RPMC funds. It focused on restoration and outreach in small sub-watershed of 35,000 acres a few miles south of Cuba, NM. The single sub-watershed was selected so that individual projects could complement each other and have a more visible impact.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;"> Headcutting is associated with piping and frequently exposes the subsoil, it is am abrupt step in the channel profile and causing channel incision. Two separate headcuts were happening in reaches of the San Pablo that were healthy. It was decided that the headcuts would need to be stabilized (usually done through gully fill) so the area might withstand seasonal flash floods without eroding. A "Fence-Out" project was also done to help keep a 1,000 ft stretch of the creek to become heavily vegetated to reduce erosion. The area had been prone to trash dumping by prior landowners which kept vegetation from growing. This was done in cooperation with the current owner who did most of the field work and technical support from the RPMC.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">LA VENTANA – a straightened stretch of the Rio Puerco south of the village of Cuba on BLM land: <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">This area was eroded and contributed extreme amounts of sediment and thus turbid flows. It is thought to have eroded 14.1 million cubic feet of sediment (Coleman 2003). The channelization happened in the 1960s with the building of a highway nearby. This section, like most reaches subjected to channelization, adjusted by incising and widening.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">In the 1950s, Highway 44 was built along the floor of the Rio Puerco Valley. A straight diversion was excavated on the west side of the roadway to “prevent erosion,” it was 5,400 feet long and 20 feet wide and 20 feet deep. Stream flow to this portion, which used to meander naturally, was now funneled into a channelized ditch. The reduced length caused the river to "downcut" when waters traveled faster with seasonal floodwaters. With time, the channel dropped about 60 feet and widened to greater than 300 feet wide in places. It was considered nonpoint source pollution to the downstream reaches of the river because of the sediment loading and because of destruction to the riparian habitat. It impaired water quality through turbidity, temperature, siltation, damage to fish (the river is State designated as a coldwater fishery), damage to riparian and macroinvertebrate habitat, and bank destabilization. EPA funds were used in 1999 to rebuild meanders. Former Hwy 44 is now Highway 550 and the highway department built bridges with this revamp.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">At the end of 2004The BLM moved dirt and rock to create a "middle meander" and focusing on the "North Rio Puerco Bridge" zone, where a transition was made from a channelized segment redirecting the river's flows back into a natural channel and under some new bridges. This work was finished in 2006 and vegetation was planted in the redirected channel in time for a 2006 monsoon to wet the 2 1/2 mile new channel..

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Ongoing or Planned Restoration** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The Rio Puerco Alliance (RPA) made an $800,000 grant proposal to the EPA under its Targeted Watershed Grant program for work in the [|Torreon Wash] area. The Torreon wash is located in the north in the Arroyo Chico drainage portion of the Rio Puerco. This area, like most of the areas along the Rio Puerco, has sparse vegetation which contributes to the high rates of soil erosion. According to the RPA, the goal of the Torreon Wash Project is to eradicate salt cedar, increase vegetative cover by 10 -15% and riparian vegetation by 20%. In addition to increasing the amount of vegetation, the project also will also include road closures, erosion reducing structures, development of grazing management plans for ranchers, trash removal, monitoring, and education. Torreon Wash is considered culturally significant to the Navajo people. To date, the Sierra Club has aided the Ojo Encino Chapter of the RPMC in the effort to restore Torreon Wash by providing $14,000 in grant funding, removing trash, planting willows and providing volunteers to plant trees.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**RESTORATION POTENTIAL** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">Each watershed has an abundance of opportunities for restoration on various levels regardless of climate, geology, or societal aspects. However, resources are limited and it is important to choose projects carefully to optimize the use of resources versus the probable outcome. The Rio Puerco is no different and in dire need of continued restoration regardless of scale. As discussed, the Rio Puerco is the largest contributor of sediment to the Rio Grande due to poor management and degradation that occurred in the 1900's. The causes of the degradation include overgrazing, climate factors, and physical characteristics that lend themselves to high sediment discharges. Reducing the amount of sediment discharge to the Rio Puerco should be done intelligently- using monitoring practices that are well-established. Other considerations in restoration potential include funding, land ownership and management, physical limitations and water rights/use/appropriation.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">**Monitoring** <span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">In order for true success to occur in the Rio Puerco watershed, succinct monitoring must be completed and studied. Those efforts must then be applied to future projects and reiterated so that the most beneficial outcome is achieved. The Rio Puerco Management Committee, the Rio Puerco Alliance (RPA), Bureau of Land Management (BLM), NMED, USGS and others have been actively monitoring the Rio Puerco. Specifically, monitoring has occurred at locations where restoration projects have been completed to see if there has been measurable improvement.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">One example would be monitoring the removal of the invasive shrub, tamarisk. While the purpose is to reduce water loss to evapotranspiration and restore native vegetation, tamarisk control could cause unintended consequences such as streams becoming geomorphically unstable. Subsequent floods could then cause sediment erosion and transport, possibly increasing flood hazards downstream. Task manager [|Jonathan Friedman of the USGS] has three objectives: "document the changes in channel geometry resulting from tamarisk removal along the Rio Puerco west of Los Lunas," second to "document channel change at a site in the Southwest where...subsequent high flows have already occurred," and finally to "enhance...existing hydraulic model for the Rio Puerco to calculate the effect of tamarisk removal on flood attenuation and sediment transport."

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">The BLM in collaboration with the RPMC and RPA have been working together to complete the mission of the Rio Puerco Management Plan. The BLM oversees and manages the El Malpais National Conservation Area. The U.S. Geological Survey, along with other state agencies, federal agencies and universities have established sites and monitoring practices to determine sediment yield. USGS also supports Allen Gellis’ effort to create a sediment budget for the Rio Puerco. Finally, University of Vermont staff member, Paul Griemann, has been studying upland erosion rates and sediment storage with use of cosmogenic isotopes to determine causes and relationships of sediment transport in the Rio Puerco watershed ([]).

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px;">There are numerous restoration projects, monitoring projects and research being completed within the watershed and undoubtedly a significant amount of collaboration. However, the Rio Puerco remains largely barren and hence will continue to produce vast amounts of sediment. According to a 2003 proposal by the EPA, “The overall goal related to the Watershed Plan is to eliminate the water quality impairment of the listed reaches of the Rio Puerco and its tributaries” and this was directly related to a “lack of vegetative density and diversity in a region of high erosion potential and impacts resulting from habitat alteration, agriculture, rangeland impacts, resource extraction, reduction of riparian vegetation, stream bank destabilization, and road maintenance activities.”

<span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">If the agencies want to succeed in eliminating the water quality impairment within the Rio Puerco watershed, a more tactful and aggressive plan must be set in place. Revegetating the badlands of the Rio Puerco will play a key role in decreasing the amount of erosion as well as using appropriate grazing practices.

<span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">To reap the benefits of restoration in the Rio Puerco, it would be best to focus efforts within the RPMC, who as mentioned before are a group of various stakeholders with diverse political and cultural backgrounds. This would be most effective because it would allow for the greatest amount of coordination and resource pooling. While many agencies lack funding and are at risk of budget cuts, the Rio Puerco is well-documented as being a degraded watershed. The result of future restoration projects will reflect on how well stakeholders collaborated and the how much effort was put forth to restore the Rio Puerco.


 * <span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">REFERENCES **

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<span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">Antevs, E. (1952). Arroyo cutting an infilling. //Journal of Geology// 60:375–385

<span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">Bryan, K. (1925). Date of channel trenching (arroyo cutting) in the arid Southwest. //Science// 62:338–344.

<span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">Bryan, K. (1928). Historic Evidence on Changes in the Channel of Rio Puerco, a Tributary of the Rio Grande in New Mexico. //The Journal of Geology// 36:265-282.

<span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">Burkham, D.E. (1966). Hydrology of Cornfield Wash area and effects of land-treatment practices, Sandoval County New Mexico, 1951-60: U.S. Geological Survey Water-Supply Paper 1831, 87pp.

<span style="font-family: arial,helvetica,sans-serif; font-size: 16px;">Bureau of Land Management. (1993) . Environmental Assessment for the Rio Puerco Dam Maintenance Project. Environmental Assessment Number NM-017-93-33, Albuquerque, NM.

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