44 research outputs found
Topobathymetric 3D model reconstruction of shallow water bodies through remote sensing, GPS, and bathymetry
No full textSince there are no mathematical models that can calculate the Laguna de Bustillos’ water storage levels, water balance requires this data to understand the connectivity between this water body and the Cuauhtemoc aquifer. This article presents a new three-dimensional reconstruction technique based on a time series of multispectral remote sensing images, bathymetry, a topographic survey with high precision GPS, and regional contours. With the images of Landsat ETM+/OLI and Sentinel 2A from 2012 to 2013, 2016, and 2017, the contours of the water surface were extracted using the MNDWI and were associated with an elevation received from GPS. An Autonomous Surface Vehicle was also used to obtain the bathymetry of the lake. A topographic survey was carried out using GPS in populated areas, and the contour lines extracted from the INEGI Continuous Elevations Model 3.0. A DEM was constructed using ArcGIS 10.5.1, and surfaces and volumes were calculated at different elevations and compared with 16 Landsat TM/ETM+/OLI multispectral images from 1999 to 2018. The results showed that the mean of the average intersection area between the test images and the area extracted from the 3D model is above 90.9% according to the confidence interval, kappa overall accuracy 95.2–99.7%, and a coefficient 89.9–99.3%. This model proved to be very accurate on a regional scale when the water level exceeded 1971.32 meters above mean sea level and useful to evaluate and administer water resources
Single-input, multiple-output iterative algorithm for the volume, area, elevation, and shape calculation using 3D topobathymetric models
No full textMost methods for estimating the morphometric values of water bodies use equations derived from hypsographic curves or digital terrain models (DTMs) that relate depth, volume (V), and area (A), and that model the uncertainty inherent in the complex underwater morphology. This work tests the performance (precision and processing time) of an algorithm to calculate morphometric parameters of a lake that uses bathymetry and topography of the surrounding water body area. The projection of the water surface height (H) on each DTM pixel generates a water column with intrinsic attributes such as volume and area.
The process is replicated among all cells and estimates the total area and volume of the water body. If the V or A is the
input data, an algorithm that iterates height values is used to generate the new data, which is compared to the entered
value that functions as a reference. If the difference between the reference value and the calculated value is less than an
error threshold, the iteration stops, and the maximum and average depths are calculated. The raster and the shape
that represent the body of water are created. The crosscomparison of H-V-A showed that there is an error between
0.0034% and 0.000039% when any of the parameters are used as input data. Performance tests determined that pixel
dimensions are directly proportional to the processing time for each iteration. The results of the implementation of this
algorithm were satisfactory since, for the DTM of Bustillos Lake, Chihuahua, Mexico, the simulation took less than 17
seconds in at most 22 iterations
Comparison of evaporation estimates from the REEM and EEFlux models in a shallow water body. Case: Bustillos Lake, Chihuahua, Mexico
No full textWaterbody evaporation (E) within endorheic basins in semiarid areas is a critical factor in determining the water balance. Accurate E measurements can provide valuable information for the sustainable management of water resources in the face of climate change scenarios. However, evaporation can be estimated through methods as efficient as Penman using variables from agroclimatic stations, such as wind velocity, net radiation, relative humidity, and air temperature, which have a
spatiotemporal variability. Within the evaporation models based on remote sensing (RS) is the surface energy balance model (SEB), which has been applied to different methodologies and extends the measurements of evapotranspiration (ET) at a regional level. SEB-based methodologies use physical principles with minimal weather data requirements to estimate ET. Hence, this article compares two methodologies that estimate evaporation using RS: The Regional Evapotranspiration Estimate Model (REEM) and the Earth Engine Evapotranspiration Flux (EEFlux). Comparing ET measurements obtained from REEM and EEFlux for seven Landsat OLI scenes in the agriculture cycle of April to September applied against the simplified Penman equation showed that the REEM performed better (d=94%) than the EEFlux (d=68%) for the indicated period. Although the comparison of
REEM and EEFlux show accurate E measurements (REEM), gridded weather data (EEFlux) needs to improve, increasing the scale using local information
Examination of particle dispersion when saline concentrate is released in septic tank wastewater
No full textSelection of RTUs and sensors
No full textPresented at SCADA and related technologies for irrigation district modernization: a USCID water management conference on October 26-29, 2005 in Vancouver, Washington.Selecting an appropriate Remote Terminal Unit (RTU) and sensors for an automation project can be daunting. There are numerous devices available with varied capabilities and performance. Factory representatives and specifications can be misleading and confusing. Advances in the electronics industry are seeing tremendous changes and subsequently RTUs and sensors are undergoing new developments. Older models are being redesigned and in some cases losing their integrity. Efforts have been made to test various RTUs and sensors, but they have not been exhaustive and these devices will eventually become obsolete. Considering the extensive choices that are available and the changes that are continually occurring, a criteria was developed for selecting these devices for automation projects. While basic performance criteria are important, it was concluded that consulting with individuals who have used these components is the most important
Model Tractor Teaching Tool
No full textA model tractor was developed to teach students about power consumption and wheel slip of farm tractors. The model was selected because of safety and resource issues. Using this model in the lab provided a safe and quiet atmosphere where the principals of power consumption and wheel slip could be demonstrated and learned. The students that participated in the lab appeared to grasp the concepts that were presented
Growth and Performance of Guar (Cyamopsis tetragonoloba (L.) Taub.) Genotypes under Various Irrigation Regimes with and without Biogenic Silica Amendment in Arid Southwest US
No full textGuar is a potential crop that can be grown as a forage or as a seed crop in arid to semi-arid regions due to its low water requirements and tolerance to heat. Optimizing irrigation water use is important for making alternative crops such as guar a sustainable option. Amendments such as biogenic silica, a sedimentary rock from a biogenic source such as fossils, may help plants tolerate water stress due to reduced irrigation. The objective of the current study was to evaluate seed yield and attribute components and agronomic and physiological parameters for four guar genotypes (Matador, Kinman, Lewis, and NMSU 15-G1) under five drip irrigation regimes (I1-normal irrigation, I2-no irrigation at 75% pod formation, I3-no irrigation at 50% and 75% pod formation, I4-terminate irrigation at flowering, and I5-terminate irrigation at flowering + biogenic silica amendment) at Las Cruces in southern New Mexico, USA, from 2016 to 2018. On average, the I1 irrigation regime produced the highest guar seed yield (2715 kg ha−1) followed by I5 (2469 kg ha−1) from 2016 to 2018. As compared to the I1 regime, the I2 and I3 regimes resulted in a 20.8% and 23.4% decline in guar seed yield, respectively, on average from 2016 to 2018. The results suggest that the addition of biogenic silica might help to improve guar seed yield under reduced irrigation conditions and can produce comparable yields with an average of 300 mm of irrigation during the growing season in the southern New Mexico region of the Southwest US
