Rio Puerco Research Articles

Recognition, Age, and Extent of Galisteo Formation, North-Central New Mexico: ABSTRACT

Since Hayden's original definition of the Galisteo Formation, there has been some confusion over its upper and lower limits, age, and distribution in New Mexico. A measured section 1,100 m thick of the Galisteo in its type area east of Cerrillos provides a firm basis for recognition of the formation in other areas by enabling lithologic and biostratigraphic correlation of major Galisteo outcrops. Steeply dipping and locally overturned strata of yellow and brown coarse-grained and pebbly sandstone dominate the lower 353 m of this section and unconformably overlie yellow and white medium to coarse-grained sandstones of the Cretaceous Mesaverde Group. Early Eocene mammals of the Cerrillos local fauna are present in red mudstones 369 to 424 m above the Mesaverde-Galisteo contact. The upper 186 m of the Cerrillos section is dominated by yellow coarse-grained and pebbly sandstones that locally contain numerous fossil logs. Latest Eocene mammals of the Tonque local fauna are present in the upper 231 m of this section. The locally conformable contact between the Galisteo Formation and the overlying Espinaso Volcanics is at a 5-m-thick transition zone of tuffaceous clay and sandstone. Strata of the upper part of the Galisteo Formation in the Hagan basin and Rio Puerco fault zone contain mammal fossils of the Tonque local fauna and can be lithologically and biostratigraphically correlated with the Cerrillos section. Other isolated Galisteo outcrops lack fossils but can be lithologically correlated, albeit imprecisely, with the Cerrillos section. Parts of the Galisteo Formation are time equivalents of the lower Eocene San Jose Formation and the Eocene part of the Baca Formation, but lithologic and structural evidence demonstrates that the Galisteo Formation is a rock-stratigraphic unit distinct from these two formations. End_of_Article - Last_Page 564------------

A vertical groundwater movement correction for heat flow

In the presence of forced convection, there exists an energy flux cρVT, because of mass‐transported heat energy. By plotting temperature gradient versus temperature the significance of convective heat transfer can be determined. Such a plot is useful even when the flow system is not one‐dimensional or vertical. As an example of convective heat transfer, a temperature log from the Rio Puerco area of New Mexico shows that downward groundwater movement of 4.7×10−7 cm/s over a 77‐m interval can reduce the observed geothermal gradient and heat flow by a factor of 2 from 4.1 to 2.0 HFU (1 HFU = 1 μcal cm−2 s−1). Such strong perturbations of heat flow by groundwater indicate the need for deep heat flow measurements to obtain a geothermal heat flux undisturbed by near‐surface groundwater. By considering the convective flux one can use the total energy balance at the boundaries of aquifers and a semiconfining medium to obtain information about groundwater seepage within the semiconfining layer.

Tertiary Oxidation in Westwater Canyon Member of Morrison Formation: ABSTRACT

Hematitic oxidation in the Westwater Canyon Member of the Morrison Formation extends along the outcrop from the Pipeline fault northeast of Gallup, New Mexico, to the San Mateo fault north of Grants, New Mexico. The hematitic sandstone forms a broad lobe in the subsurface to a depth of 730 m (2,400 ft). The downdip edge arcs eastward from northeast Church Rock through Crownpoint, and southeastward to the west edge of the Ambrosia Lake district. The red sandstone is bordered on the downdip side by a band of limonitic oxidation which interfingers with reduced sandstones basinward. The limonitic oxidation forms a relatively narrow band along the north and west sides of the hematitic lobe, but expands progressively on the east and southeast. Weak limonitic oxidation, as indic ted by the absence of pyrite and a bleached to faint yellowish-gray color, appears to extend from the San Mateo fault eastward under Mount Taylor to the Rio Puerco. The hematitic oxidation is epigenetic and is believed to be of late Miocene to early Pliocene age. The limonitic oxidation follows the present groundwater flow pattern and probably dates from late Pliocene to recent. The oxidation patterns are important in uranium exploration because the hematitic area is essentially barren, whereas the limonitic areas contain ore deposits which are in the process of being destroyed by oxidation. End_of_Article - Last_Page 694------------

Vegetative and Reproductive Growth Patterns in Desert Willow (Chilopsis linearis (Cav.) Sweet)

The patterns of leaf and fruit production of desert willow, Chilop- sis linearis (Cav.) Sweet, in relation to temperature and precipitation patterns in the Chihuahuan Desert of southern New Mexico were examined by harvesting shoot samples monthly during four growing seasons. On a site with 1.1 individuals per hectare, leaf production was about 5 kg-ha-1 and fruit production was about 1 kg-ha-1 in two years with dry springs and moist summers. In a year with a moist spring and a moist summer, leaf and fruit production was doubled. This high rate of production in the field during favorable periods supports previous laboratory studies that Chilipsis has a high acclimation potential under cool to moderate tem- peratures. However, in a year with a hot, dry spring and summer Chilopsis was adversely affected. This also supports previous studies that the net photosynthesis rate of Chilopsis was greatly reduced under high preconditioning temperatures and rapidly decreased as water potentials dropped below - 10 bars. Desert willow, Chilopsis linearis (Cay.) Sweet, is a small, deciduous tree. It varies from 4 to 9 m in height, with numerous long branches and willow-like leaves. The white flowers are orchid-shaped with purple stripes. The fruits are 10 cm or more long, and narrow, with wings of the seeds dissected into hairs (Kearney and Peebles 1960). Chilopsis occurs throughout the desert areas of the southwestern U.S. and northern Mexico (Hastings, Turner and Warren 1972). In the Sonoran desert, it occurs along the larger drainage channels with mesquite and other species requiring the more favorable moisture con- ditions of this riparian habitat (Shreve 1964). In the southern New Mexico region of the Chihuahuan desert, it is also restricted to larger drainages. Freeman and Dick-Peddie (1970) found Chilopsis in lower elevation riparian habitats of the Sacramento Mts., but not in similar habitats of the Black Range. Gardner (1951) found it in large arroyos and tributaries to the Rio Grande from the mouth of the Rio Puerco south to Las Cruces. Balding and Cunningham (1974) described the

Tectonic development of the northeast part of the Rio Puerco fault zone, New Mexico

Research Article| November 01, 1975 Tectonic development of the northeast part of the Rio Puerco fault zone, New Mexico Paul B. Slack Paul B. Slack 1Cities Service Oil Company, 900 Colorado State Bank Building, 1600 Broadway, Denver, Colorado 80202 Search for other works by this author on: GSW Google Scholar Geology (1975) 3 (11): 665–668. https://doi.org/10.1130/0091-7613(1975)3<665:TDOTNP>2.0.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Paul B. Slack; Tectonic development of the northeast part of the Rio Puerco fault zone, New Mexico. Geology 1975;; 3 (11): 665–668. doi: https://doi.org/10.1130/0091-7613(1975)3<665:TDOTNP>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The major structural features of the northeast part of the Rio Puerco fault zone are (1) north- to northwest-trending folds, (2) northeast-trending normal faults, and (3) north-trending normal faults. These structures formed in response to an older north-oriented shear couple and a younger east-west-oriented tension. Laramide orogenic movements of late Paleocene through Eocene age resulted from a north-trending, right-shift force couple related to northeast shift of the Colorado Plateau. The folds and the northeast-trending normal faults formed in response to the right-shift couple, and the faults are interpreted as tensional fractures that developed at 45° to the trend of the couple. Miocene to Holocene tectonism is dominated by north-trending, east-dipping normal faults related to the development of the Rio Grande rift. Many southeast-dipping normal faults of Laramide origin were rejuvenated during Miocene and younger rifting. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Nearest Neighbor Analysis of Pueblo I-III Settlement Patterns along the Rio Puerco of the East, New Mexico

AbstractNearest neighbor analysis, a method which quantifies the deviation of a body of data from a random toward either a clustered or an anticlustered distribution, was utilized to study aspects of a settlement system. Data from a surface survey of 241 Pueblo I-III sites on the middle Rio Puerco of the East, New Mexico, corroborated the hypothesis of a direct correlation between house location and presence of arable land, assuming use of akchin farming methods. A smooth curve of population growth and decline was correlated with a decrease, then increase, in site agglomeration. Presumably these changes reflected adjustment of site locations to a deteriorating environment resulting from the shift to a summer rainfall cycle. Statistical tests corroborated the validity of these observations. Arrangement of the ceramic types according to their corresponding degree of aggregation produced a tentative local ceramic chronology.

Structural Geology and Tectonic Development of Northeast Part of Rio Puerco Fault Zone, Sandoval County, New Mexico: ABSTRACT

The northeast part of the Rio Puerco fault zone is in the southwestern part of Sandoval County, New Mexico. Three major types of structural features are present within the area: north- to northwest-trending folds; northeast-trending faults of the Rio Puerco fault zone; and north-trending faults. Dominant movement along faults within the area is dip-slip. Two major periods of deformation are evident, the Laramide orogenic movements of late Paleocene through Eocene age, and Basin and Range tectonism of middle Miocene to recent age. Laramide tectonism resulted from a north-trending right-shift force couple related to the northeast drift of the Colorado Plateau, and to vertical forces which led to the development of the Nacimiento uplift. The northwest-trending folds and the northeast-trending normal faults of the Rio Puerco fault zone formed in response to the right-shift force couple. The Rio Puerco faults are interpreted as tension fractures which developed at 45° to the trend of the force couple. A slight clockwise rotation of the southeast part of the Colorado Plateau is evident from tension fracture trends along the fault zone. Miocene tectonic activity was dominated by north-trending, east-dipping normal faults having large stratigraphic separations that were related to the development of the Rio Grand rift. Many of the southeast-dipping normal faults of the Laramide Rio Puerco fault zone were rejuvenated during the Miocene crustal extension. End_of_Article - Last_Page 918------------

Vegetation Changes as a Result of Soil Ripping on the Rio Puerco in New Mexico

Vegetation Changes as a Result of Soil Ripping on the Rio Puerco in New Mexico

Germinable Alkali Sacation Seed Content of Soils in the Rio Puerco Basin, West Central New Mexico

Barren sites are interspersed through native stands of alkali sacaton (Sporbolus airoides Torr.) in west central New Mexico. To determine if these sites remain bare because of lack of viable seeds, soil samples were collected three times each year for three years, and emerging sacaton seedlings were counted. Fewer germinable seeds were found in soil from barren sits than in soil from within stands. Moreover, the number of germinable seeds varied with time of collection. Seed movement from stands to barren sites were determined through collection made weekly during the period of seed dissemination. It was found that a substantial number of alkali sacaton seeds cross the barren sites, mainly through wind action. As many as 40—50 seeds/sq. ft. (400—500 m2) were collected 25 to 50 feet (7.6 to 15.2 m) from established stands. The results suggest most seeds are blown across the barren sites. The few seeds trapped in microsites in the soil soon after dissemination apparently are either removed by wind water animals, or insects, or are killed due to unfavorable moisture—temperature conditions.

Stocking Rangelands on the Rio Puerco in New Mexico

Stocking levels, utilization percentages, and perennial grass forage production were recorded from 1958 through 1969 on the San Luis Experimental Watersheds in the Rio Puerto Basin, 58 miles northwest of Albuquerque, New Mexico. Over two-thirds of the 3,900,OOO acres of the Rio Puerto is composed of rangelands similar to those in the experimental watersheds. From 12 years of data on part of the watershed, we have developed tables to use as guidelines for stocking semidesert ranges in central New Mexico, where summer deferment is practiced. These are applicable on semidesert ranges found on most of the Rio Puerto drainage. The portion of the watershed used for this study is a 525-acre experimental range unit, pasture II, in the transition zone between woodland and semidesert grassland (Aldon, 1964). Cattle grazed the area each year from November 1 through April 30. Principal forage species, in descending order of cattle preference (Aldon and Garcia, 1967), are alkali sacaton (Sporobollcs airoides (Torr.) Torr.), galleta (Hilaria jamesii (Torr.) Benth.), and blue grama (Bouteloua graciks (H.B.K.), Lag. ex Steud.).

Hyperconcentrations of Suspended Sediment

Extremely high suspended sediment concentrations in streamflow, those exceeding 40% by weight, are shown to consist largely of sands with an apparent minimum fine material concentration of approximately 15% by weight. X-ray diffraction analyses of the clay fractions show mostly montmorillonite and illite with some kaolinite. The volume occupied by the suspended sediment becomes appreciable at these higher concentrations, averaging 5.8% of the total runoff volume for the period 1948-1962 for the Rio Puerco in New Mexico and the Paira River in Arizona. No relation was found between streamflow discharge and the magnitude of hyperconcentration. Particle-size distributions of Paria River suspended-sediment samples appear to consist of two log-normal subdistributions: One of material finer and one of material coarser than 0.062 mm.

Study of Channel Erosion and Sediment Transport

Observations of channel erosion, flow, and sediment transport for the Rio Puerco, in New Mexico, indicate that the characteristics of the channel and of the channel material change rapidly because of deposition and erosion, and that the ephemeral flows carry extremely high concentrations of suspended sediment that influence flow and transport characteristics.

Ecological Notes on the Mammals of Bernalillo County, New Mexico

Bernalillo County is a nearly rectangular area, measuring approximately 40 by 80 miles and located in north-central New Mexico. Aside from being a center of population, agriculture, and historical interest, the area deserves attention because of its fortunate combination of geographic features. It is almost evenly bisected into east and west halves by the Rio Grande. The eastern half includes a section of the Sandia and Manzano mountain ranges, while the western half consists of high mesas and a small desert river, the Rio Puerco. With its long axis running east and west, the county itself makes a transect across these formations. This paper is a progress report summarizing notes on the ecological distribution of mammals collected intermittently between September, 1947, and June, 1956, by the writer. About 6,000 trap-nights in 23 localities form the basis of the report. Trapping was principally with small metal live traps of the Sherman...

Paul Reiter 1909-1953

American AnthropologistVolume 56, Issue 6 p. 1085-1087 Free Access PAUL REITER 1909–1953 Clyde Kluckhohn, Clyde Kluckhohn Harvard UniversitySearch for more papers by this author Clyde Kluckhohn, Clyde Kluckhohn Harvard UniversitySearch for more papers by this author First published: December 1954 https://doi.org/10.1525/aa.1954.56.6.02a00100Citations: 13AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References Cited 1930 “Cave investigated”. El Palacio 29: 269– 72. 1931 Airplane used in archaeological survey of Pueblo Plateau. El Palacio 30: 215– 17, 224–25. 1931 Preliminary examination of a ruin in the Rio Puerco Valley, New Mexico. El Palacio 31: 414– 16. 1933 Ancient Pueblo of Chetro Ketl. M.A. thesis, University of New Mexico. Unpublished. 1935 With H. G. Alexander. Report on the excavation of Jemez Cave, New Mexico. Monographs of the School of American Research, No. 4. Albuquerque, University of New Mexico Press. 1938 The Jemez pueblo of Unshagi, New Mexico; with notes on earlier excavations at “Amoxiumqua” and Giusewa. Monographs of the School of American Research, Nos. 5–6. Albuquerque, University of New Mexico Press. 1939 Preview of a ruin. New Mexico 17, No. 7: 14– 15, 42–44. 1939 Ed. with Clyde Kluckhohn. Preliminary report on the 1937 excavations, Bc 50–51, Chaco Canyon, New Mexico, with some distributional analyses. Albuquerque, University of New Mexico Press. 1940 With W. T. Mulloy and E. H. Blumenthal, Jr. Preliminary report of the Jemez excavation at Nanishagi, New Mexico. University of New Mexico, Bulletin. Anthropological Series, Vol. 3, No. 3. 1940 The Southwest before Coronado. El Palacio 47: 108– 10. 1946 Form and function in some prehistoric ceremonial structures in the Southwest. Ph.D. thesis, Harvard University. Unpublished. Citing Literature Volume56, Issue6December 1954Pages 1085-1087 ReferencesRelatedInformation

A Remark on the Puente‐Ladron, New Mexico, Aerolite

ABSTRACTThere is ample evidence to support the belief that the American Indians collected meteorites and preserved them for longer or shorter periods, during which, in some cases, the meteorites were transported over considerable distances. The strip of country along the Rio Puerco, within which the Puente‐Ladron, New Mexico, aerolite was found, was one of the main highways of Amerind traffic and a favorite camping and hunting ground until very recent times. Unless it can be shown that the aerolite in question was not transported into this area by an Indian and there discarded or lost, an all‐out search of the Puente‐Ladron area for other members of the shower to which it has been conjectured the stone belongs does not seem justified.

TERTIARY AND QUATERNARY GEOLOGY OF THE LOWER RIO PUERCO AREA, NEW MEXICO

The eastern part of the Lower Rio Puerco area is located in the Albuquerque-Belen basin, a subdivision of the Rio Grande depression, which in turn is an extension of the Basin and Range physiographic province. The western part is in the Colorado Plateaus. The Albuquerque-Belen basin was formed in the late Tertiary by downwarping and downfaulting. Streams eroded the Carboniferous and Mesozoic sedimentary rocks and the early and middle Tertiary volcanic rocks and deposited the sediment in the depression. Contemporary vulcanism produced local basaltic lava flows. The basin deposit and the interbedded basalt constitute the Santa Fe formation. The basin deposit consists of a maximum of 4800 feet of alluvial-fan beds, axial river gravels, and playa beds. The proportion and detailed lithology of these types depended upon the rate of uplift and erosion of the highlands, the rate of subsidence and deposition in the basin, the lithology of the source rocks, and the climate. Study of the horizontal and vertical differences in lithology in the Santa Fe formation reveals the changing physiographic and dynamic relations of the Rio Grande depression and bordering highlands during the late Tertiary. These relations are shown on two paleogeographic maps. The western border of the Albuquerque-Belen basin is marked by a complex fault zone which was established as a zone of weakness during the early Tertiary warping of the Colorado Plateaus. The late Tertiary Santa Fe basin deposit overlapped this border, but accelerated subsidence of the basin produced faults along the old fault zone, and the Santa Fe formation is now delimited on the west by late- and post-Santa Fe faults which have a maximum displacement of 6300 feet. The main period of late Santa Fe and post-Santa Fe deformation was followed in the early Pleistocene by a period of crustal stability, during which time the extensive Ortiz erosion surface was developed on the deformed Santa Fe and older formations. This erosion surface was graded to an ancestral Rio Grande 400-500 feet above the present Rio Grande. A paleogeographic map was prepared with restored contours to show the drainage lines on this surface within the Albuquerque-Belen basin and the plateau contry to the west. Renewed regional deformation, marked locally by small faults, initiated a major stream piracy and the general dissection of the extensive Ortiz surface. Subsequent erosion and regional changes in base level have produced from two to four post-Ortiz erosion surfaces along the major streams of the Lower Rio Puerco area, with gradients 250–300, 175–200; 100–150, and 50–75 feet respectively above those of the present streams. Areas covered by maps in this paper are outlined. Stippled pattern shows Rio Grande depression. 1. Physiographic provinces of north-central New Mexico (Fig. 2). 2. Paleogeographic map for Ortiz time (Fig. 12). 3. Fault pattern of western border of Albuquerque-Belen basin (Fig. 9). 4. Paleogeographic maps for Santa Fe time (Figs. 4, 5). 5. Lower Rio Puerco area (Plates 8, 10). All the erosion surfaces in the Lower Rio Puerco area are covered and in part protected by stream gravel, caliche, wind-blown sand, travertine, or basaltic lava flows. The geomorphic map of the area shows the distribution of these different covers as well as the distribution of the remnants of the surfaces themselves.

Sources of Modern Sands in the Middle Rio Grande Valley, New Mexico

In the Middle Rio Grande Valley, New Mexico, serious flood damage, drainage impairment, and soil impoverishment are occurring as a result of the accumulation of modern sediment. The relative importance of various sources of the injurious sediment, which is largely sand, has been determined from the heavy-mineral composition of channel deposits of the Rio Grande and its tributaries. It was found that about 48-54 per cent of the Rio Grande channel and floodway sand deposits between San Acacia and San Marcial have come from the Rio Puerco, 19-21 per cent from the Rio Salado, and 25-33 per cent from the rest of the drainage basin. The Rio Puerco drains about 21 per cent of the watershed, and the Rio Salado about 6 per cent. Of the channel and floodway deposits between Albuquerque and Bernardo, about 21-39 per cent have come from the Rio Jemez, 2-6 per cent from the Rio Galisteo, 0.6-2.0 per cent from Santa Fe Creek, 11-37 per cent from the Rio Grande above Cochiti, New Mexico, and the rest from small tributaries for which separate evaluations were not made. Tributary contributions to the main stream apparently did not change greatly during the five-year period of investigation, 1937-41. Since 1880, however, there have been marked changes in contribution from some tributaries and in the mineral composition of the Rio Grande sands between San Acacia and San Marcial. All source evaluations were based on the hydraulic ratios of the heavy minerals. The reasons why other methods of representing mineral compositions are not suitable for source evaluations are outlined.

Alluvial Sites of Central New Mexico

In the upper Rio Grande valley, presence of the Sandia and Folsom cultures,1 has accentuated two important archaeological problems: that of bridging the gap, no matter how long or short, between the approximate 25,000 year date given for the Sandia Culture and the subsequent period of Folsom occupation;2 and that of reconstructing some sort of chronology between the Folsom period and the generalized Basketmaker era. The latter perhaps involves an 8,000--10,000 year chronological blank in central New Mexico. Several factors may aid in building up the chronological stability highlighted by these problems: (1) deposits of geologic significance in relation to time and events, (2) animal remains in relation to dating geologic deposits, (3) and culture remains in association with animal remains or alone in geologic deposits. It is in hope of adding an iota of material toward an eventual solution of these problems that the following resume of part of the earlier work, and the citation of new material, is presented. In 1938 Bryan and Butler found campsites on the Arroyo de Cordito, six miles south of Tres Piedras, New Mexico, and on a terrace on the west side of the Rio San Antonio, about one mile northwest of the base of San Antonio Mountain. The artifacts found were scrapers, knives and points. The conclusion was advanced that a group having a plains type of culture was present in this region.3 On the Rito de los Encinos, near Youngsville, New Mexico, a tributary of the Rio Puerco which in turn joins the Chama, Bryan found early, intermediate and late alluvium. In the late alluvium appeared hearths and many flint chips.4 In the intermediate alluvium an ax, two choppers, and a scraper were found. This Bryan has named the Los Encinos Culture.5 In the older alluvium, preceding the intermediate alluvium, Bryan found remains of a proboscidian.6 In 1940 a group of surface and buried hearths were found by the writer at Coyote Springs, nine miles southeast of Albuquerque. The

Quaternary Geology of the San Acacia Area, New Mexico

At San Acacia the Rio Grande passes through a narrow canyon which separates the southern end of the broad Albuquerque-Belen Valley from the northern end of the Socorro Valley. Los Pinos Mountains lie to the east and the Sierra Ladron to the west. The Socorro Mountains separate the Socorro Valley from the higher Snake Ranch Flats and Magdalena Mountains to the west. Deformation in post-Santa Fe (post-Pliocene?) time produced the present basins and determined the location of the principal highlands and main drainage lines. In general, the mountain blocks are composed of relatively resistant pre-Tertiary rocks and Tertiary volcanic rocks, the lowlands of unconsolidated Tertiary basin deposits. The four pediment remnants present in the area and their projected grades above the present flood plains are: Feet Ortiz (?) pediment..................... 370-400 Tio Bartolo pediment.................. 250 Valle de Parida pediment............... 150 Canada Mariana pediment.............. 50-75 Their origin is discussed briefly. A cut-and-fill terrace at about 100 feet above the present flood plains is found in some places. The probable development by piracy in post-Ortiz time of the Rio Puerco and of the present course of the Rio Salado is discussed. Ancient and modern sand dunes and ventifacts, recent channel incision (arroyo cutting), and caliche on pediment surfaces are briefly mentioned.

Progress‐report of the National Research Council Interdivisional Committee on Density‐Currents

During the past year the Committee has concentrated its efforts on securing evidence as to the occurrence of silt‐laden currents of water at the bottom, of Elephant Butte Reservoir and of Lake Mead. As reported last year in these Transactions, programs of cooperative field‐observations and laboratory‐studies in which a number of bureaus of the Federal Government were to participate were prepared at a meeting of the Committee in June 1937. These programs were carried out in somewhat modified form through the cooperative efforts of the United States Geological Survey, the United States Bureau of Reclamation, the Division of Western Irrigation Agriculture of the United States Bureau of Plant Industry, the United States Bureau of Fisheries, the International Boundary Commission, and the National Bureau of Standards. The United States weather Bureau office at Albuquerque also contributed by furnishing warnings of flood‐flows on the Rio Puerco, and the Metropolitan Water District of Southern California assisted by analyzing samples of water from Lake Mead. The present progress‐report is not complete, since information as to some parts of the program carried out will not be available until the next meeting of the Committee, presumably in June, 1938. However, sufficient interesting data are available, particularly from Lake Mead, to warrant presenting it at this time.