Table 1 shows the statistical parameters of calibration and validation data. The maximum value of calibration period was larger than that of the validation range while the minimum value was less than that of validation. Thus, extrapolation problems may not exist in this data set. The skewness in both calibration and validation data sets are not drastically different. At the forecasting station, the autocorrelation and partial autocorrelation functions of water level with corresponding confidence limits were estimated up to 20 lags as shown in Fig. 4. The ACF for many successive lags was quite high in the water level series as a signal of high persistence. The PACF indicates a significant correlation up to lag 4. Thereafter, correlations fell within the confidence limits. In this case, five delay water levels at times (t-1) to (t-5) were considered as inputs.
The cross correlations between water levels and rainfalls during flood season were also determined to estimate the degree to which two variables are correlated. It was found that the water level was less correlated with its at-site rainfall although the positive relation was shown up to 8 previous rainfalls. The CCFs of five antecedent rainfalls are 0.16, 0.17, 0.16, 0.15, and 0.13, respectively, and considered as predictor variables. The number of input was directly determined by the number of lagged values to be used for forecasting of the next value. The general function of input-output relations for both SMLR and ANN models are as follows:
Case – 1 Ht to Ht+4 = f [ Ht-1,Ht-2, Ht-3, Ht-4, Ht-5]
Case – 2 Ht to Ht+4 = f [Ht-1,Ht-2, Ht-3, Ht-4, Ht-5, Rt-1, Rt-2, Rt-3, Rt-4, Rt-5]
Where t = time (day), H = water level and R = rainfall
The output water levels (H) at time ...
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...while the predicted values marginally agreed with the observed ones in Aug 2008 and 2011. Overall, their performances are not very different in terms of R2. It was found that both models slightly under predicted the high floods in rising limb while over predicted the falling limbs, caused by the effects of antecedent water levels. The models could not fully capture the underlying mechanism of the rising and falling rates of high floods. In the case of extreme events, the MAPE is 1.5% for SMLR and 1.4% for ANN models. Minimum and maximum percent errors ranged between 0.09% and 7.4% in the SMLR models while 0.05% and 6.7% in the ANN models, respectively. Thus, particularly ANN models have a lower error range than the SMLR in predicting high floods. It seems that ANN models better generalize the variability of high floods in the observation period than SMLR models.
New Orleans, Louisiana lies at the second lowest elevation among major cities in the United States. It is a city surrounded by water, making it almost like an island. To counter this dangerous combination of the low elevation along with the lakes, rivers and swamps surrounding it, the Army Corps of Engineers built a series of levees around the city to foster its protection. It is these very same levees however that might doom the city should a Category 3 hurricane ever hit. Our statistical analyses examined the current belief that there is a 39% probability that New Orleans will be hit by a major hurricane and based on the resulting Z-score, rejected that belief. We did find however that the probability, while not 39%, was still in the 30th percentile range, which should still be a major cause for concern among the leaders and residences of the city of New Orleans.
A major flood on any river is both a long-term and a short-term event, particularly any river basin where human influence has exerted "control" over the ri...
Already scientists have observed that more than 75% of the recent economic losses are caused by natural hazards which can be attributed to wind storms, floods, droughts and other climate related hazards. In the year 2008, the U.S. state of Iowa was on the front pages of newspapers all around the world. Weeks of heavy rain in the Midwest caused rivers to swell and levees to break. Millions of acres of farmland are now underwater, their plantings most likely destroyed. By March, Iowa had tied its third-highest monthly snowfall in 121 years of record keeping, and then came the rain. April’s st...
The Midwestern United States has experienced flooding for a long time now, but recently the annual precipitation has been far greater than before. Precipitation has increased 37 percent since 1958 (Jeff Spross). However a few major floods have been recorded dating back to 1913. In 1913 torrential rainfall hit Indiana and Ohio. The ground was greatly damaged from the flood causing difficult agricultural years for many years after the flood. Another flood hit a large portion of the Midwest region including the eastern Dakotas, Wisconsin, Kansas, and Indiana in 1993. Recovery costs for the Great Flood exceeded $4.2 billion. Like the flood in 1913 agriculture was affected for many years hurting the economy of the Midwest. A more recent disastrous flood hit mainly Iowa in 2008. After the flood in 2008 agriculture again took a hard hit and since the government ...
In the binational area of El Paso, Texas and Ciudad Juarez flooding has become a way of life due to the scarcity of rain and desert climate. Fortunately, meteorologist, geologist and city planners are continuously working to improve city prior to a storm in order to mitigate any financial hardships during and after a flood. The city has to take in account past events in order to improve infrastructure. They also rely on meteorologist to study how the weather is reacting so they can anticipate the next system and how it will hit this region. The primary expert that contributes to this vital research are the Geologist, who have brought to light the cause and effects during drastic climate events. In this report, it will document infrastructure affects, stormwater management, Climate Whiplash and thoughts from the geologist on the desert-flood relationship.
National Weather Service. National Oceanic and Atmospheric Association, 5 Jan. 2010. Web. 2 Feb. 2010. .
References: Mairson, Alan, "The Great Flood of '93," National Geographic, vol. 93, pages 93-93. 185 (January 1994), pp. 187-187. 42-81. The s. National Biological Service, Department of the Interior, "Environmental Management Technical Center," http://www.emtc.nbs.gov (1996).
Cities in Texas are especially vulnerable to the effects of climate change. Depending on where they are located, cities vary in their vulnerability and most major cities face a decline in water resources. Coastal cities, such as from Houston to the Rio Grande, are exposed to a rise in sea level. The decline of fresh water reservoirs and the rising sea level ...
"Forecasting Effects of Sea-Level Rise and Windstorms on Coastal and Inland Ecosystems." Frontiers in Ecology and the Environment 6.5 (2008): 255-63. JSTOR. Ecological Society of America, June 2008. Web. 11 Feb. 2014.
New Orleans flooding risks originated from its location characteristics in proximity of Mississippi River. Since its foundation up to 1927, New Orleans water and flooding threats originated from Mississippi River but human activities had contained this by 1930s. Regrettably, this led to additional water problems. Accordingly, the critical changes to the New Orleans environment originating from the human development worsened the water problems in area caused by the floods. In particular, the growth in ...
A draft is a form of a social obligations that is just not an ordinary obligation, but it is a legal one. The government is behind it which means that the government has the right to draft you into war whether you agree with it or not. In The Things They Carried, Tim O’Brien was trapped between the sword and the wall on the decision of going to war or escaping the draft by going to Canada. He had to choose whether or not to risk his life for the sake of his country and family. Throughout the chapter entitled “On the Rainy River” Tim O’Brien tells us the readers how hard was for him to make a decision of whether to go or not. Tim O’Brien puts us on his position by asking rhetorical questions such as “What would you do?” “Would
The role of relationship you have with other people often has direct influence on the individual choices and belief in the life. In the short story “on the rainy river”, the author Tim O’Brien inform us about his experiences and how his interacted with a single person had effected his life so could understand himself. It is hard for anyone to be dependent on just his believes and own personal experience, when there are so many people with different belief to influence you choices and have the right choices for you self. Occasionally taking experience and knowledge of other people to help you understand and build from them your own identity and choices in life.
...xpected weather conditions over time, previous weather conditions, possible areas of less deteriorating weather conditions, expected duration of bad weather condition.
A Flood Hydrograph and the Factors That Affect its Form A flood hydrograph is a graph of two axis, 'discharge' and 'time'. Plotted on the graph is the amount of discharge over a period of time. By looking at a hydrograph, a lot of information and data can be gathered about the river, the precipitation, the surrounding area and vegetation etc. The gradient, height and length of a line can tell you a lot of this information. There are many different factors that can affect the appearance and shape of a hydrograph.
The purpose of this paper is to explain the advances being made in technology and algorithms in helping advance the accuracy of forecasting. It will contrast the forecasting methods of several decades ago with forecasting methods in use today. In discussing how errors can accumulate over time and providing simple mathematical formulas as examples, this paper intends to show how the repetition of minor errors can affect the accuracy of weather predictions.