Chowchilla Subbasin Case Study

3. Statements (1) and (2) refer to water amounts. Are these Net or Gross amounts? (1) Crop water

A major problem in Southern California is that Los Angeles experiences very little rain all year, followed by intense downpours that last less than one day (53). Its unreliable rainfall severely hurts the region. In Northern California, mountains such as the Sierra Nevada allow for a huge range in rainfall over a short distance. “…a place on the western slope of the range may receive eighty or so inches of precipitation in a year, while a place on the east slope, fifty miles away, may receive ten inches or less” (58).

As the days are becoming hotter, and as our water supply is decreasing, it is becoming more relevant than ever before to increase the water inventory for the agricultural industry. With the damming of the Hetchy-Hetchy river, it will limit our already low supply and output of crop, which is the lead export of sustenance in the nation.

The minor aquifers are Dockum, the Capitan, the Rustler, the Hickory, the Ellenburger- San Saba, the Lipan and to a small amount Marble Falls (Anaya 2001, 113). The aquifer is mostly unconfined but is semi confined in parts of the Trinity (Anaya 2001, 113). The direction of the groundwater flow is controlled by the areas of discharge, which are displayed by the strong influence of the streams form on the potentiometric surface (Barker and Ardis 1996, 35). The predominant direction of the groundwater flow is northwest to southeast, caused the base slope of the aquifer (Barker and Ardis 1996, 35). This flow is also normal to the potentiometric surface as shown in figure 3, except where the aquifer is anisotropic (Barker and Ardis 1996, 37). Most of the recharge that occurs in the Edward-Trinity aquifer happens from infiltration of precipitation over the outcrops and the sinkholes (Anaya 2001, 113). The average recharge rate over the eastern part of the plateau is 0.12 to 2.24 inches per year whereas over the Trans-Pecos region is 0.3 to 0.4 inches per year (Anaya 2001, 113). In certain areas of the plateau such as Pecos and Reeves counties there is induced recharge being caused from the water level declines due to irrigation pumping (Anaya 2001, 116). Discharge occurs in the southern and eastern portions from cross-formational flow

Surface water commonly is hydraulically connected to ground water, but the interactions are difficult to observe and measure (Winter, 1998). Interaction depends upon understanding the effect of topography, geology and climate of the groundwater

Where AET is actual evapotranspiration, P is the precipitation depth, and Q is runoff depth. Combined evaporation and transpiration from plants (evapotranspiration) is balanced by inflows as precipitation and outflows as runoff. Based on a research conducted by McGuiness (1963) for a period of seventeen years (1933-1949), the Rock Creek basin received an average precipitation of 43.5 inches, in which 12 inches was surface runoff. Therefore, if the precipitation and runoff values are substituted into the equation above, actual evapotranspiration rate of the basin equals 31.5 inches. However,

Yuma and some surroundings agricultural areas are a flooding plain. This makes the soil very fertile and good for planting many different vegetables and plants. Yuma has virtually 3 days of sunshine with sparse mounts of rain. The Colorado river is very close to Yuma, at a couple points crossing through it. This serves as a main source of water for the acres of farming land available. “I stopped at Yuma on my return from Colorado to examine the conditions under which irrigation has been practiced on the Algodones Grant with a view to determine whether or not gravity canals are likely to prove feasible for the general irrigation of that district, as against pumping. The following report has been prepared to embody my conclusions on the matter.

The water level (observed) and water level (simulated) water levels and the variation over time were graphed below in figure 5.

The depth of the A horizon is 0-4 inches. This horizon is a loamy soil with a color of 2.5YR 4/2. This horizon usually contains many grass roots which have decomposed to help form this organic material and this soil profile.. This horizon mostly has a weak crusty plate like structure but can also be granular. Ph for horizon A fall around 7.5 -8 on average. Horizon A also has mild carbonates which lead it to have slight effervescent when hydrochloric acid is applied. This horizon which is mostly dominated by grasslands which penetrate the soil and allow water to better infiltrate and a rock content no greater than 5% by volume.

The 1KB14 catchment with steep slope showed higher T values than the gentle slope 1KB4 catchment. However, no significant relation was found between the elevations of individual wells location and T derived from pump test of wells. The higher T estimates derived from the small-scale measurement could either infer high heterogeneity of aquifer within the valley specifically, 1KB17 catchment, difficulty of measurement technique, and limited number of measurements.

Conductivity is the measure of how well water can conduct an electrical current (Shahady, 2010). At each creek cite the conductivity varied, at Claytor – Big Otter was record to be at 57.5 µs/cm, making it the lowest record for the whole study. Peaksview – Ivy Creek was record at 108 µs/cm and Target – Rock Castle Creek at 285 µs/cm, the highest recorded. The term pH is used to indicate how alkaline or acidic water is determined on a scale from 1.0 to 14.0 (Shahady, 2010). The pH at each different creek seemed to be around the number. At Claytor – Big Otter it was record to be 7.0 and at Target – Rock Castle Creek was 7.65, this means that the water is alkaline, meaning there are more hydroxide ions than hydrogen ions. Claytor – Big Otter

Next we will discuss the Florida Aquifer System. There are many factors that contribute to the storage and movement of ground water, porosity and permeability are the two most important elements to this equation (Lutgens, 2012.) Porosity is the volume of open space between rock or sediment and permeability is the ability for a fluid to pass through (Lutgens, 2012.) Rock and sediments that allow groundwater to travel freely are called aquifers. These aquifers are natural resources that exist underneath the earths surface to store water. In the case of Florida’s aquifer system the system is considered to be one of the most productive in the world (USGS, n.d.) In its entirety, the aquifer system “underlies an area of about 100,000 square miles

At the height of the drought between 2014 and 2015, the surface reservoirs received a water loss of 8.7 million acre-ft from its preliminary water level of 18.125 million acre-ft (R. Howitt, Medellín-azuara, & Macewan, 2015). With a 48% loss, the amount of water that is easily accessible to the farmers decreases. The decrease in the annual precipitation and the loss of water storage causes the amount of the idle land to be developed during this drought to increase by

Evapotranspiration (ET) is a primary component of determining crop water requirement and ultimately irrigation requirement. ET consists of transpiration of water from plants and evaporation of water from the soil surface. 65% of the precipitation is lost into the atmosphere through evaporation and transpiration (Kite, 2000).Potential evapotranspiration (PET) is a representation of the evapotranspiration rate of a short green crop (grass/alfalfa), completely shading the ground, of uniform height and with adequate water status in the soil profile. Analysis of potential evapotranspiration (PET) is essential in irrigation water management and planning.

During Monsoon, different loses occurs in storing structures of surfaces because of high evaporation. Evaporation of barren soil along with the combined process involving evaporation, gaseous state transformation and transpiration of the water from the surface of earth into atmosphere increases the exhaustion of soil moisture thereby decreasing the quantity and rate of soil permeation. The overall result is reducing the overflow production potential.